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205 Cards in this Set
- Front
- Back
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ECONOMIC IMPACTS OF WEED |
- yield loss due to competition - yield loss die to parasitism (dodder, mistletoes, striga, broomrapes) - reduced yield quality - loss of operational efficiency - reduction in land value |
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ENVIRONMENTAL IMPACTS OF WEEDS |
- displace native vegetation - alternate food source for other pests - host for other pests - clog aquatic systems |
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AESTHETIC IMPACTS OF WEEDS |
- In various ornamental settings - perception of farming |
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HEALTH AND SAFETY IMPACTS OF WEEDS |
- poisonous and allergenic - fire hazard - block visibility of safety signs/equipment |
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Multiple pests with weeds |
Multiple pest attack can lead to synergistic increases in damage, and alteration of single pest economic thresholds |
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Arthropods within-field that feed on weed |
Cutworms, flea beetles, two-spotted mites, whiteflies |
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Pathogens within-field that feed on weed |
Rhizoctonia, Verticillium |
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Vertebrates within-field that feed on weed |
Mice, voles, ground squirrels |
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Mollusks within-field that feed on weed |
Slugs and snails |
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Nematodes within-field that feed on weed |
rootknot, cycst and others |
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Alternate host of Maize dwarf mosaic (WDMV) |
Echinochloa, Leptochloa, Digitaria, Setaria, Sorghum halapense |
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Alternate host of Rice tungro, RTSV |
Eleusine, Echinochloa crus-galli and E. colonum (both symtomless), Leersia |
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Alternate host of Tobacco mosaic, TMV |
Chenopodium murale, Plantago, Erigeron |
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Alternate host of cucumber mosaic, CMV |
Amaranthus, Capsella, Convolvulus arvensis, Brassica |
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Alternate host of Root-lesion nematode |
Xanthium, Digitaria, Sonchus, Cynodon +55 others |
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Alternate hosts for Sugarbeet cyst nematode |
Chenopodium album, Brassica spp., Amaranthus retroflexus |
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Alternate hosts for Soybean cyst nematode |
Stellaria, Lamium, Lespedeza, Sesbania and 1100 others |
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Alternate hosts for Root-knot nematodes |
Cyperus spp., Digitaria, Amaranthus, Capsella, Setaria, Chenopodium +70 others |
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Alternate hosts for Rice root nematode |
Cyperus spp., Rottboellia, Echinochloa, Oxalis, Cynodon, and many others |
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Nusedges and rootknot nematode |
- Up to 250-fold increase in nematodes on the weed - they reside in tubers - Infection is essentially symptomless and does not alter tuber production |
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Standard nematode management recommendation |
rotate to non-host crops |
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Weeds provide oviposition sites: |
Southern corn rootworm: grasses Alfalfa weevil: henbit (Lamium amplexicaule) Predaceous earwig: Johnsongrass (Sorghum halapense) |
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Weeds provide overwintering sites: |
Rice water weevil adults survive in Paspalum dilatatum on levees |
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Weeds provide what for rodents: |
Cover |
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Monocot weeds |
Grasses and sedges |
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Number of seeds produced per plant: |
between 50 (Field bindweed) and 229,175 (Redroot pigweed) |
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Weed seed germination as affected by certain conditions: CATTLE FEEDING |
For redroot pigweed - 98% before feeding and %12 after Buckhorn plantain - 94% to 0% Wild oats - 74% to 0% |
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Weed seed germination as affected by certain conditions: STORAGE IN SILAGE |
Barnyardgrass - 61% month before storage and 0% after 4 weeks Yellow foxtail - 20% before and 0% after Common lambsquarters - 82% before and 0% after Wild mustard - 93% before and 0% after |
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Weed seed germination as affected by certain conditions: BURNING |
- Impact seeds on plants more than seed on the soil surface - seed destruction depend on intensity and duration - moderate heat may end seed dormancy |
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Weeds life cycle and control: Annual summer and winter |
Control at 1 to 2 inches |
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Weeds life cycle and control: biennial |
treated like annual |
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Weeds life cycle and control: perennials |
Seedling, treated like annual Established, at bolt stage |
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Weed management: mechanical practices |
Plowing, Row crops cultivation, hoeing, mowing, mulching, and burning |
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Weed management: cultural practices |
Crop selection, crop varieties (chemical vs. nonchemical), planting date, plant population and spacing, and fertility and irrigation |
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Weed management: biological control |
Insects, pathogens, herbivores |
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Issues of biological control |
- Selective - effective on invasive plants in rangeland - long process - suppressed weed population to threshold level - no complete control - environment may effect establishment and suppression |
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Example of unexpected consequences |
- myxomatosis introduced into Australia to control rabbits - incidence of lettuce necrotic yellow virus increased - rabbits ate sowthistles which are an alternative reservoir host for the virus - after rabbit population decreased sowthistles increased = more virus inoculums |
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Weed management: chemical weed control (herbicide) |
- mycoherbicide/bioherbicides - organic herbicides - synthetic herbicides |
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Herbicide Classification |
- time of application - area of application - action of herbicide - herbicide translocation -mode of action - chemistry |
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Time of application: PREPLANTING |
Herbicide application is made before crop is planted and before weed emergence |
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Time of application: PREEMERGENCE |
Herbicide application after crop is planted but before weeds and crop emerge |
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Advantages of PRE treatment |
- plant crop and apply herbicide in a single operation - herbicide may be applied in bands |
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Disadvantage of PRE treatment |
- rain or irrigation are necessary to move herbicide into weed seed zone - herbicide loss by volatility and/or photo-decomposition - adverse climatic conditions may prevent timely application |
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Time of application: POSTEMERGENCE |
Herbicide application after emergence of crop and or weeds |
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Advantages of POST treatment |
- low rates of herbicides usually required - apply when problem is exist - cost effective
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Disadvantages of POST |
- In general, do not provide broad spectrum weed control - Efficacy dependent on climatic factors - poor weed control with late application - crop injury risk - some weed competition occurred before herbicide application |
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What are vertebrate pests? |
Nonhuman species of vertebrate animals that are currently troublesome locally, or over a wide area, to one or more persons, wither by being a health hazard, a general nuisance, or by destroying food, fiber, or natural resources |
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Importance of biology/ecology |
Understanding the biology and ecology of vertebrate pests will guide management decisions |
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Management strategy |
- Identify the vertebrate pest species - Assess options for managing this species - Develop and implement a management plan you deem most appropriate - Monitor after implementation to effectiveness and to assess potential reinfestations |
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Species Identification (Ground Squirrels) |
- Gray - brown fur with semi-bushy tail - Social - active throughout the day and frequently visible - prefer to burrow next to buildings, on field edges and alongside fencerows and roadsides |
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Damage of Ground Squirrels |
Damage includes girdling of trees, consumption of forbs and grasses, chewing of irrigation lines, and abundant burrow openings |
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Species identification (Pocket Gophers) |
- burrowing rodent about 6-8 in long; rarely seen above ground - mounds are plugged and often fan-shaped |
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Damage of Pocket Gophers |
- They feed on taproots weakening and/or killing plants - they can girdle trees, particularly below ground - mounds can also kill plants and can create weed seed-beds |
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Species Identification (Meadow Voles) |
- Have dark grayish brown fur and are 4-6 inches in length - populations tend to cycle, exhibiting irruptive growth patterns
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Damage by Meadow Voles |
- Dig shallow burrows and leave well-worn trails - primary damage caused by girdling of stems and gnawing of irrigation pipe |
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Species identification: Norway rats, roof rats, house mouse, deer mouse |
- Primarily commensal rodents - can be difficult to control in agricultural settings |
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Species Identification: Tree Squirrels |
- 4 species found in CA (Fox squirrel causes the most damage) - are diurnal - will consume nut crops, dig holes in lawns, chew on cables, and nest in buildings |
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Species Identification: Hares and Rabbits |
- Jackrabbits are hares, but they are the most common rabbit-like pest - are larger and have longer ears than cottontails - damage caused through foraging on stems and leaves of plants |
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Species Identification: Cottontails |
- True rabbits - they are smaller and have shorter ears - They don't typically cause much damage as jackrabbits but can be localized pests |
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Species Identification: Raccoon and Opossum |
- will eat fruits and vegetables - can get into garbage and pet foods - potentially transmit diseases |
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Species Identification: Skunks |
- Will dig holes looking for grubs and insects - will spray - will eat pet foods - can transmit diseases |
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Species Identification: Wild Pigs |
- Are social - Primary damage caused through rooting activities for plants and insects |
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Species Identification: Deer |
- can cause significant damage to crops, especially when fields are in close proximity to forested and riparian areas - most damage will occur during dawn, dusk, and at night, so identification of footprints and scat may be needed to determine deer were the cause of damage |
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Species Identification: Coyote |
- harass and kill livestock - chew irrigation line - dig burrows |
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Species Identification: birds |
- damage and consume a number of crops - include ducks, geese, crows, magpies, starlings, house finches, and scrub jays |
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Control Options: Biocontrol |
-natural predators have been used to control vertebrate pest populations - falconers seem to work - bird boxes are inconclusive at best - gopher snakes kill a few but are unlikely to control populations |
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Control Options: Habitat Modification |
- involves altering habitat to reduce the desirability for pests - remove brush piles to control ground squirrels - control vegetative growth to reduce cover for voles |
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Control Options: Exclusion |
- wire baskets can be used to exclude gophers - fencing and tree protectors can reduce or eliminate damage caused by voles, rabbits, and deer |
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Control Options: Repellents |
- rely on objectionable odors or unpleasant tastes -can work for a short while, but effectiveness is spotty and usually only temporary |
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Control Options: Trapping |
- Control of small populations of rodents, rabbits, and some birds - effective at certain times of the year when other methods are less effective and can be a good follow up to alternative control methods
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Categories of traps |
- Kill traps - live traps |
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Kill traps |
- body-gripping traps, box-type squeeze traps and pincer traps |
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Live traps |
Wire cage traps (require euthanization of vertebrate pests) |
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Control Options: baiting |
Anticoagulants |
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Anticoagulants |
- used for spot treatments, broadcast, or in bait stations - require multiple feedings |
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Bait stations |
- commercial - upside down T - modifications to upside down T - use in K-rat territory |
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Zinc Phosphide |
- is an acute toxin - potential bait shyness - can be used for spot treatments and broadcast baiting - not to be used in or around buildings |
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1st Generation anticoagulant: positive attributes |
- lower primary nontarget risk - antidote available - good bait acceptance - readily available |
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1st Generation anticoagulant: negative attributes |
- require larger amount of bait - some potential for secondary risk - slower time to death than other toxicants - is restricted-use material |
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Zinc phosphide: positive attributes |
- short time from consumption to death provides quick control - less expensive than anticoagulants - essentially no secondary risk |
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Zinc phosphide: negative attributes |
- acutely toxic; primary risks can be high for aboveground applications - bait acceptance can be poor - precipitation can influence efficacy - no antidote - is restricted use material |
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Control Options: Fumigation |
- involved use of poison gas in burrows to control vertebrate pests - works best when soil moisture is high - fumigants should not be used around buildings |
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Aluminum phosphide |
- tablets can be used for ground squirrels and gophers - is a restricted use pesticide |
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Gas cartridges |
- only work on ground squirrels - caution must be used with gas cartridges to prevent fires |
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Monitoring for vertebrate |
- regular check for sign of vertebrate pests - follow up control methods can be used to eliminate individuals that were not removed during initial control efforts |
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What is plant pathology? |
- study of plant diseases - causes of plant diseases - development - disease management |
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Plant diseases |
Persistent or simi-persistent condition involving an abnormality in structure or function of a plant induced by a biotic or abiotic factor and that reduces the economic or aesthetic value of a plant or group of plants |
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Symptoms of disease |
the outward or visual manifestation of the abnormal condition (implies that you are familiar with the normal plant) |
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Signs of disease |
the physical presence of the pathogen on or in diseased plant tissue (mistletoes, powdery mildew, rust, ect) |
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Biotic causal agents of disease |
Fungal, viruses, viroids, bacteria, phytoplasmas, nematodes and parasitic plants |
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Abiotic causal agents of disease |
Air pollution, herbicide damage and excesses and deficiencies in water and nutrition |
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Emerging diseases |
new diseases that have become a problem or known disease that have become more of a problem, often due to a change in some aspect of the pathogen biology |
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Fungi |
- most are saprophytes, obtaining nutrition from decaying organic matter, and are beneficial - many fungi have evolved to parasitize plants and these are the most economically important pathogen group - obligate (need living plants to grow and reproduce) - non-obligate (can grow independently) |
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obligate fungi |
downy mildews smuts rust fungi |
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non-obligate fungi |
wide range of fungi that cause leaf spots and blights, root rots, fruit spots and rots and other diseases |
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Identification: Fungi |
- tend to be microscopic organisms, but most grow in culture or produce characteristic structures that allow for their identification - main structures are mycelium (made up of hyphae and spores)
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Fungi spores |
- spores can be produced asexually or sexually - spores and spore-producing structures can be important for identification and diagnosis
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Fungi life cycle |
- overwinter in association with perennial host tissues or seeds and in debris - spread to new plants via wind and rain - overwintering occurs as mycelium, asexual spores, specialized sexual structures or hardened mycelial structures (sclerotia and stroma) |
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Plant pathogenic prokaryotes: characteristics |
- microscopic, single-celled organisms - have a cell membrane or that and a cell wall - no nucleus or organelles but have small ribosomes in their cytoplasm - sensitivity to antibiotics - major groups of prokaryotes: bacteria and phytoplasmas |
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Bacteria |
- 1 X 3 micrometers - most are saprophytes - some cause serious disease of animals and humans - 200 species cause plant disease
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Bacteria shapes |
- rod-shaped (most plant pathogenic bacteria) - spherical - ellipsoidal - spiral - comma-shaped - and filamentous |
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Symptoms induced by plant pathogenic bacteria |
- leaf spots and blights (G. Pseudomonas and Xanthomons) - Vascular wilts and blights (G. Ralstonia, Clavibacter, and Erwinia) - Bacterial soft rots (G. Pectobacterium) - Tumors and galls (G. Agrobacterium) |
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Life cycle and spread of bacteria |
- survive in association with perennial plant organs, seeds, transplants, insects, or in soil and debris - favored by moist, humid conditions - favored by wounding or damage
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Bacteria spread by insects |
Sharpshooters spread Xyllela fastidiosa (Pierces disease of grapevine) Asian citrus psyllid spreads causal agent of citrus greening disease (Candidatus Liberibacter asiatius) |
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Plant virus characteristics |
- submicroscopic rogue infectious nucleoprotein entity consisting of genetic material that is covered by a protective shell of protein - ultimate parasites - trick the cell into producing viral nucleic acids and proteins instead of normal cellular components - strictly obligate parasites |
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Plant viruses classification |
- second most important to fungi - 1000 plant virus species - characterized based on virion type, genome type and sequence |
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Plant virus: identification |
- commonly identified by the symptoms induced - most distinctive symptom is the mosaic or mottles - can mimick abiotic problems such as nutrient deficiency and herbicide damage - induced symptoms include stunted growth and distortion and color changes in leaves, stems and fruits |
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Plant virus: life cycle and spread |
- spread by insect vectors - long distance spread is via seed, plant materials and insects carried on plants and wind currents - host range varies greatly |
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Phytoplasmas |
- cell wall-less bacteria that live in phloem of plants - induced yellowing and witches broom symptoms - transmitted by leafhoppers and psyllids - aster yellows and pear decline |
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Parasitic plants |
- extracting water and nutrients from other plants - cause reduction in growth and yield - leafy and dwarf mistletoe and dodder |
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Nematodes |
- microscopic worm-like organisms that live in soil - feed on plant roots, bulbs, and other organs - can cause significant damage to plants
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New diseases |
- sudden oak death (Phytophthora ramorum) - citrus greening disease (Candidatus liberobacter) - whitefly-transmitted germiniviruses - thrips-transmitted tospoviruses |
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Old diseases |
- late blight of potato - downy mildew of cucurbits - stem rust of wheat (new Ug 99 race) - pierce's disease of grapevine (Xylella fastidiosa) |
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Abiotic diseases |
- result of imbalances of certain factors/substances, often as a result of human activities - cannot be transferred
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Abiotic Diseases Examples |
- water deficiency - water excess - nutrient deficiency or excess - pesticide toxicity - sunburn - frost damage - air pollution - too much or too little light - ice damage/hail damage
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Multiwell Enxyme-linked immunoasay (ELISA) |
- detect various viruses - also for bacteria and fungi |
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Immunostrips |
A rapid and precise method for detection of viruses including Tobacco mosaic virus, Cucumber mosaic virus, Tomato spotted wilt virus and other viruses and bacteria |
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Stages in the development of disease |
- inoculation - penetration - infection - dissemination - overwintering and/or oversummering |
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Inoculation |
form of the pathogen coming in contact with the host |
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Penetration |
the means by which the pathogen inoculum gains access to the host. This can be direct or via wounds |
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Infection |
process by which the pathogen invades the host and is able to multiply and extract nutrients from the host |
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Dissemination |
spread of the pathogen, generally passive and mediated by air, water, insects, animals and humans |
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Overwintering and or oversummering |
how the pathogen persists in the absence of the host. In association with the host plant, in association with insects. The formation of resistant structures and eggs and seeds. |
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Integrated Pest Management (IPM) |
An approach that combines multiple management strategies (biological, cultural, genetic and chemical) selected based on knowledge of the biology of the pathogens |
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Three basic steps of IPM |
- correct pathogen ID - understanding pathogen biology/disease epidemiology - development and evaluation of a management strategy |
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IPM combines: |
the use of biological, cultural, physical and chemical methods in a manner that strives to minimize economic, health and environmental risks |
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IPM components: integrated |
involves multiple approaches |
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IPM components: preventative |
some approaches are designed to maintain pest populations at low levels (in the presence and absence of the crop) |
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IPM components: knowledge-based |
Is based on an in-depth understanding of pathogen biology and ecology (know your enemy) |
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IPM components: management and control |
rather than elimination/eradication. Keep pest problems within tolerable limits (levels that are low enough to avoid intolerable damage) |
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IPM management strategies |
- regulatory (quarantine) - avoidance - disease resistance (conventional and transgenic) - pathogen-free propagative materials - disease monitoring and forecasting to identify conditions - pesticides -crop rotation - crop-free periods - sanitation |
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Symptoms of fire blight in apples and pears |
- rapid blighting or death of flowers and twigs, development of cankers on large branches, and death of young trees - a diagnostic symptom is the presence of wilted twigs that turn brown-black with the tip handing down - signs of the disease include bacterial oozing from infected flowers, twigs and even fruits |
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Fire blight: causal agent |
- gram-negative bacterium: erwinia amylovora - colonis are white, mucoid and convex |
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Fire blight: disease cycle |
- overwinter in cankers on branches of perennial trees - bacterial ooze from cankers - spread to flowers by water and insects - bacterial populations build-up on flowers and shoots - infections occur in flowers - cause collapse and tissue death - move short distances in xylem |
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Fire blight canker symptoms |
bark around infected branches becomes watersoaked, sunken and dries. Infections progress into the trunk and large branches, resulting in cankers |
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Fire blight predictive model |
- based upon the knowledge of the biology of the bacterium and how and where the bacteria infect the plant - measure factors such as temperature, rainfall, leaf wetness and presence of blossoms - other factors include when flowers appear on trees and history of blight in the area |
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Additional practices for fire blight |
- plant resistant varieties or rootstocks - prune blighted tissues 8-12 inches below canker - apply a dormant copper spray to reduce bacterial populations |
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Additional practices for fire blight: growing season |
- promptly remove infected branches - avoid excessive nitrogen fertilization - avoid overhead irrigation - manage insects with sucking mouthparts - monitor temperature and other factors |
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Materials that can be applied for fire blight management |
- antibiotics - copper materials - biocontrol with bacteria and Blightban |
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IPM of insect-transmitted plant viruses |
- need to consider both the virus and the vector - difficult to establish thresholds - difficult in virus identification - insect vectors can become resistant to insecticides and virus can overcome host resistance |
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Arthropods |
- exoskeleton - grow by molting - jointed appendages - crabs, centipedes, spiders, mites, insects |
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Order Coleoptera: Beetles |
- chewing mouthparts - complete metamorphosis |
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Oder Dermaptera: Earwigs |
- chewing mouthparrts - gradual metamorphosis |
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Order Diptera: Flies |
- rasping, sponging, or sucking mouthpoarts as adults - hook-like chewing mouthparts as larvae - complete metamorphosis - one pair wings |
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Oder Hemiptera: True bugs |
- Piercing-sucking mouthparts - gradual metamorphosis |
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Order Hemiptera (formerly Homoptera): Aphids, scales, whiteflies, mealybugs |
- sucking mouthparts - gradual metamorphosis |
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Order Hymenoptera: wasps and ants |
- chewing mouthparts - complete metamorphosis |
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Order Lepidoptera: butterflies and moths |
- mouthparts reduced in adult. - chewing in larvae - complete metamorphosis |
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Order Orthoptera: Grasshoppers, crickets, katydids |
- chewing mouthparts - gradual metamorphosis |
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Order Neuroptera: lacewings |
- chewing mouthparts - complete metamorphosis |
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Order Siphonaptera: fleas |
- complete metamorphosis - piercing-sucking mouthparts |
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Order thysanoptera: thrips |
- intermediate metamorphosis - sucking mouthparts |
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What makes insects and other arthropods pests? |
- plant damage by chewing insects - damage by sucking insects - vector pathogens - structural damage |
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Vector pathogens that cause disease |
- malaria - west Nile Virus - Western equine encephalomyelitis - Lyme disease - Chagas disease - plague - rocky mountain spotted fever |
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Insects that cause structural damage |
- termites - wood-boring beetles - carpenter ants - carpenter bees |
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Monitoring and decision making for insects |
- arthropod development largely regulated by temperatures - degree-days help predict timing of treatment activities for some insects - sampling guidelines coordinated with quantitative treatment thresholds are available for many major ag insect pests |
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Monitoring techniques for insects |
- visual - yellow sticky trap - pharomone trap - beating tray - double sided sticky tape - water sensitive card to monitor honeydew |
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Preventive methods for insects |
- eliminate food sources - eliminate harborages or overwintering sites - plant pest-resistant varieties or species - plant pest-free planting stock or seeds - exclusion-screens, greenhouses row covers etc. - maintain healthy plants that can tolerate some damage |
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Cultural management practices for insects |
- planting dates to avoid pests - remove weeds around vegetable fields at least 2 weeks before planting to reduce cutworm invasions - reduction of dust to reduce spider mites in strawberries, cotton and other crops - harvest almonds before 3rd generation of navel orangeworm eggs laid - harvest alfalfa to avoid alfalfa caterpillar problems |
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Physical and mechanical controls of insects |
- traps (yellow jackets) - barriers (sand barriers for subterranean termite) - shredding crop residues for pink bollworm in cotton - chipping wood to reduce bark beetle and borer infestations |
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Insecticides in IPM programs |
- used when monitoring and treatment guidelines indicate need - choose products that are least toxic to beneficials and honeybees - consider the environment and human health - Avoid resistance problems |
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Old insecticide groups (potential environmental problems) |
- Organophosphates (OPs) - Carbaryl (Sevin) - Pyrethroids - Neonicotinoids |
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Low toxicity insecticide (IPM compatible) |
- oils and soaps reduce populations - Bacillus thuringiensis kurstaki - botanical insecticides - insect growth regulators - pheromone applied for mating disruption |
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Oils and soaps reduce populations of: |
- aphids - immature scales - immature whiteflies - thrips - lacebugs - psyllids - spider mites |
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Botanical insecticides |
- derived from plants - organically acceptable if not formulated with nonorganic inerts - various modes of action and toxicities - generally break down rapidly - common products are pyrethrins and neem based products (azadirachtin) - rotenone, sabidilla - nicotine sulfate (very toxic and not available) |
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Insect growth regulators |
- interfere with insects' normal development such as molting, chitin synthesis, reproduction or egg hatch - very low toxicity to mammals but some can be toxic to predatory beetles - safe for bees |
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Pheromone applied for mating disruption for: |
- oriental fruit moth in stone fruits - codling moth in apples and pears - peach twig borer in stone fruits - navel orangeworm - vine mealy bug in grapes |
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Key insect pests in almonds |
- navel orangeworm - peach twig borer |
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Other important pests in almonds |
- spider mites - ants - san jose scale - plant bugs - leafrollers - ten lines june beetle |
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Navel orangeworm (Ameylois transtiella) |
- became the key pest of almonds in teh late 1960s, probably because of a rapid change in mechanical harvesting practices - more nuts remained on trees, providing overwintering sites |
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Most chemical controls for arthropods are: |
therapeutic or suppressive |
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most cultural control for arthropods on almonds are: |
preventative |
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Almond IPM based upon cultural controls |
- early harvest - now egg trap - rapid nut pickup - winter sanitation - orchards with <2 mummies per tree often won't need sprays |
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Outcomes of early research and extension activities for IPM on almonds: |
- 30% reduction in total damge - 44% reduction in navel orangeworm treatments - $7 million annual reduction in pesticide costs - $10 million annual reduction in damage |
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Peach Twig Borer |
- prior to the 1960s, it was the key pest of CA almonds - When sprayed for in May, outbreak of spider mites increases to damaging levels - Also kills natural enemies of spider mites |
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Dormant sprays |
dormant season sprays also control European red mite, brown almond mite and San Jose scale |
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Benefits of dormant sprays |
- multiple pests controlled - pest life stages synchronized (timing easier) - cheap - less worker exposure in winter - less concern for biocontrol agents in winter - fewer nontarget vertebrates active - no residues on food |
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Control of peach twig borer |
could be controlled at bloom just as it is emerging from its protected hibernacula with spray of the environmentally begin insecticide Bacillus thuringiensis (Bt) - Bt is safe to use around pollinators at bloom |
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Other pests treated in the dormant season could be controlled with oil alone - or sometimes didn't need treatment |
European fruit scale, brown mite eggs, San Jose scale black caps, and red mite eggs |
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Spider mites |
- Pacific spider mite (Tetranychus pacificus) - Twospotted Spider mite (Tetranychus urticae) - secondary pests become a huge problem in orchards and key reason for impleminting IPM |
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Why do spider mites become problems? |
- usually there is some kind of disruption - the drying of almond orchards in preparation for harvest makes them particularly vulnerable to spider mites |
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Spider mite management |
- horticultural practices that avoid plant stress - spider mite sampling - avoid use of disruptive pesticides - conservation and release of predatory mites - low rates of selective miticides |
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Spider mite sampling |
action threshold is 4 mites per leaf |
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Spider mite natural enemies |
- include a number of generalist predators as well as predatory mites, especially the western orchard predator mite - Galendromus occidentalis - increased use of organophosphates for navel orangeworm control in late 70s and 80s induced spider mite outbreaks |
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The greatest current challenge to CA's almond IPM program is the continued use of pyrethroid insecticides: |
their use is driven by low cost (ignoring secondary outbreaks of pests like spider mites), high crop value, and increased emphasis on very low crop damage. |
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Argentine Ant (Linepithema humile) |
- most common pest entering homes in CA - native to S. America, entered CA in early 1990s - displaced many native species - about 85% of PMP calls in SD. 42% in SF - one node, monocolor - have musty odor and does not sting |
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Why are Argentine ants successful? |
- aggressive toward other ants - do not compete among themselves - colonies are joined together with more than one queen - very large and diffuse colonies |
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Carpenter ants - Camponotus spp. |
- one node - don't feed on wood but their nests can compromise structural integrity - winged males appear in spring |
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Roles of ant castes |
- Queens establish new nests, lay eggs, 15/1000 - males mate with queens, appear in spring - workers search for food, feed the colony, defend the nest |
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Argentine ant colony numbers increase by budding |
- one or more queens and workers and brood move to new location - no clear delineation between colonies - free flow of workers between colonies - thus Argentine ant colonies are linked throughout neighborhoods - workers forage over several hundred feet |
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Nest in shallow mounds |
- under soil - under debris, mulch wood - often along sidewalks driveways - near moisture and food sources |
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What do ants eat? |
all year round - sweets spring - proteins |
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Why are Argentine ants pests? |
- protect honeydew producing insects - outcompete and displace native species - invade homes and become a nuisance |
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Prevention is key for ants |
- understand food and nesting requirements of ants and remove them - seal up entryways - remove limbs and travelways into home - remove shrubbery and nesting substrates around foundation - don't allow sprinklers to water areas next to foundation - fix leaky faucets |
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Why are baits effective for ants? |
- they attract worker ants - baits kill the ants in the colonies, not just the visible ones - it could take 7-10 days or more before you see results |
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A PCA is any person who |
- offers a recommendation on any agricultural use of a pest control product of technique - presents themselves as an authority on any agricultural use - or solicits services or sales for any agricultural use - must be licensed by the CA department of pesticide regulation |
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Agricultural use is |
use of any pesticide, method or device for the control of plant or animal pests or pesticides for regulation of plant growth or defoliation of plants for commercial production of plants or animals as well as applications in parks, golf courses, waterways, forests, roadsides, right-of-ways, cemeteries and similar areas |
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US EPA |
- regulates pesticides nationally through the federal insecticide, fungicide and rodentcide act - registers pesticides and puts restriction on their use that PCAs must follow - no specific national laws or regulations related to PCAs |
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CA Department of Pesticide Regulation (DPR) |
- regulates under the laws contained in the CA food and agriculture code - can be more restrictive than US EPA, but not less - pesticides must be registered both by US EPA and CA DPR |
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County Agricultural Commissioners (CACs) |
- enforce pesticide laws at the local level - may develop pesticide use policies - PCAs must be registered with them - may inspect PCA records - good local source of information on pesticides |
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Certified Crop Advisers |
- Sponsored by the American Society for Agronomy - CCA Pest management certification will not substitute for a PCA license in CA |
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Certify crop consultants in |
- nutrient management - soil and water management - crop management - pest management |
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Services provided by PCAs |
- specific recommendation for a pesticide or pest control - expertise for planning - monitor for pests on a regular basis/ written updates to property owners - worker training - may provide advice related to fertilizers or other practices - assist growers in implementing IPM programs - assistance in qualifying for organic certification programs or other specialty certification programs |
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Requirements for becoming a PCA |
- satisfy educational requirements to qualify to take exam - pay a fee - pass an exam on laws and regulations and principles of IPM plus an exam in at least one subject matter area |
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Subject matter categories for PCA |
- insects, mites, and other invertebrates - plant pathology - nematology - weed science - vertebrate pests - defoliation - plant growth regulators |
