- Author: Surendra K. Dara
“Integrated pest management (IPM) is an ecosystem-based strategy that focuses on long-term prevention of pests or their damage through a combination of techniques such as biological control, habitat manipulation, modification of cultural practices, and use of resistant varieties. Pesticides are used only after monitoring indicates they are needed according to established guidelines, and treatments are made with the goal of removing only the target organism. Pest control materials are selected and applied in a manner that minimizes risks to human health, beneficial and nontarget organisms, and the environment.” UC IPM
IPM is pivotal in providing effective and sustainable management of pests and diseases in various crops. University of California has an extensive IPM program with sound science-based solutions for numerous pests, diseases, and weeds. One of our approaches is to provide guidelines for year-round IPM to help mitigate environmental health issues while providing practical management options.
Year-round IPM program enables the growers to make appropriate decisions before and throughout the growing season to avoid or mitigate pest problems. From choosing the right field or ideal cultivar to timely harvesting of fruit or postharvest field sanitation are important in avoiding several problems. Here is a brief overview of year-round strawberry IPM.
Before planting
Crop rotation: It eliminates the availability of host plants for pests or diseases. Rotating strawberries with nonsusceptible hosts minimizes the risk of diseases such as angular leaf spot, anthracnose, charcoal rot, Fusarium wilt, and Verticillium wilt.
Field selection: A clean, well-drained field free of diseases or away from sources of pest infestations will reduce the risk of some diseases like Fusarium wilt and pests like lygus bug and spider mites. Fields close to second-year strawberries or can have early infestations of certain pests.
Cut-back strawberry field to extend the production season. They harbor pests that can contribute to infestation of the nearby new fields. (Photo by Surendra Dara)
Fumigation or solarization: Several soilborne diseases and weeds can be effectively controlled through fumigation or solarization (where practical). Studies with non-chemical fumigation techniques such as anaerobic soil disinfestation are under way and can provide alternative solutions to chemical fumigants.
Cultivar selection: Choose a cultivar that is resistant to major pests and/or diseases.
Weed management: Several flowering weeds serve as a source of lygus bugs. Managing such weeds in winter reduces the risk of lygus bug.
Plastic mulch: Using a mulch that promotes healthy plant growth helps plants withstand some disease and pest issues.
At planting
Clean and strong transplants: Angular leaf spot, anthracnose, common leaf spot, phytophthora crown rot, powdery mildew, and pallidosis-related decline of strawberry are among the diseases that can be introduced to the production fields through infected transplants. Pests like spider mites and cyclamen mites can also be brought in through transplants. Inadequate or excessive chilling of transplants can result in reduced yields and predispose plants to pest or disease problems. Obtaining transplants from a reputable nursery is always a good investment.
Planting: Adequate spacing and other care while planting are important for optimal plant growth and yield as well as reducing the risk of certain diseases.
After planting
Irrigation: Since strawberries are sensitive to salinity, good water source is important for plant health. Excessive drip or overhead irrigation causes several disease problems such as angular leaf spot, common leaf spot, and red stele. Water stress can weaken plants and worsen the spider mite problem.
Nutrition: Optimal fertilizer supply is important for a healthy crop and good yields. Excessive nitrogen application can worsen some pest problems or diseases like powdery mildew and Verticillium wilt.
Sanitation: Removal of infected or old fruit or plant material is important for minimizing botrytis fruit rot, leather rot, mucor rot, and Rhizopus fruit rot. This practice also important in managing spotted-wing drosophila or other such pests.
Removing dead and dried leaves and leftover berries as a part of good field sanitation rotine. (Photo by Surendra Dara)
Regular monitoring: Regularly monitoring fields for pest, disease or other problems and taking preventive or proactive measures is critical. Proper sampling techniques are important for making treatment decisions.
Pesticides: Timely application of right pesticides is critical in preventing and minimizing the problems. Rotating chemicals with different modes of action increases the control efficacy and reduces the risk of resistance. If insecticide resistance is suspected, test over a small area or on suspected populations before large scale application.
Biological control: Conserve natural enemies by providing alternate hosts as refuges and by using softer chemicals. Good natural enemy populations play a major role in managing pest populations. Predatory mites are effective in controlling spider mites, but choosing the right species at the right time is important.
Releasing the right species of the predatory mite appropriate for the season can play a major role in controlling spider mites. (Photo by Surendra Dara)
Microbial control: In recent field studies, the entomopathogenic fungus, Beauveria bassiana showed a potential for managing aphids, lygus bug, and spider mites.
Botanical pesticides: Recent field trials produced promising results with azadirachtin, a neem-based insect growth regulator in managing some pests including lygus bug.
Other measures and all-time care with good agricultural practices are important for a successful IPM. IPM is an ecosystem-based strategy for a long-term prevention of pests or their damage through a combination of various techniques. Pesticides are used only as necessary with appropriate materials that have minimal risk to humans, non-target organisms, and the environment.
Additional details on various pests, diseases, and weeds, sampling procedures, survey forms, management options, and year-round strawberry IPM program can be found at the following UC resources:http://www.ipm.ucdavis.edu/PMG/C734/m734yi01.html and http://www.ipm.ucdavis.edu/PMG/selectnewpest.strawberry.html.
View new year-round IPM program video & year-round IPM programs to protect cole crops and pistachio from agricultural pests
Got pests and want to use integrated pest management? Use a year-round IPM program. If you're not familiar with what a year-round IPM program is, think of it as a checklist for the agricultural pest management activities you should be doing throughout the season. Take the new video tour “Using Year-Round IPM Programs” to explore the benefits and uses of IPM in field, orchard, and vineyard crops. Managing pests in Cole Crops and Pistachio? View our two newest year-round IPM programs.
Monitoring the most important pests, making management decisions, and planning for the following season are all activities in the year-round IPM programs. Even better are how they connect to the Pest Management Guidelines so you can read about the details…how to monitor, what the treatment thresholds are, or the best pesticide to use.
One of the basic IPM principles is to choose the best pesticide for the situation. The year-round IPM programs help you do this by ensuring you're applying pesticides only when you need to, and providing you with information so you can choose the most effective pesticide with the least harm to water quality, air quality, natural enemies, and honey bees.
The checklist, photo ID pages, and monitoring forms are easily printable for use in the field. Interested in other crops? We have 25 year-round IPM programs:
- Alfalfa
- Almond
- Apricot
- Asparagus
- Avocado
- Cherry
- Citrus
- Corn
- Cole crops
- Cotton
- Cucurbits
- Dry Beans
- Grape
- Lettuce
- Nectarine
- Peach
- Pear
- Peppers
- Pistachio
- Plum
- Potato
- Prune
- Strawberry
- Tomato
- Walnut
Let us know how year-round IPM programs are benefiting you.
Thank you,
Tunyalee Martin, tlamartin@ucanr.edu
Jodi Azulai, jlazulai@ucanr.edu
Romy Basler, rbasler@ucanr.edu
http://www.ipm.ucdavis.edu/IPMPROJECT/about_yrp.html
www.ipm.ucdavis.edu
- Author: Surendra K. Dara
Some Santa Maria strawberry growers experienced heavy infestations of whiteflies last year and there are already reports of infestations in some fields this year. Greenhouse whitefly, Trialeurodes vaporariorum has been a common strawberry pest in California for the past few years occasionally reaching high infestation levels that require targeted treatments. It used to be a concern mainly in the Oxnard area. Presence of the cut-back strawberries for second year production aid prolonged presence of whiteflies in the area and contribute to the early season infestations in new plantings.
Life stages of the greenhouse whitefly: Eggs darken when they are close to hatching. First instar nymphs are mobile and called crawlers. Later instars are immobile. Fourth instar nymphs are called pupae and characterized by long, waxy filaments. Adults have waxy, white wings. Black sooty mold grows on the honeydew secreted by whiteflies. (Photos by Jack Kelly Clark, Frank Zalom, and Surendra Dara)
Direct and indirect damage: Whitefly feeding affects plant growth and reduces yield and fruit quality. As they consume large quantities of plant sap, whiteflies excrete sticky honeydew deposited on the plant. Fungi of a few genera develop as black sooty mold on the honeydew covered surfaces. Sooty mold interferes with photosynthesis and affects plant growth. It also reduces the quality of the fruit.
Disease transmission: Greenhouse whiteflies are also important as vectors of pallidosis-related decline of strawberries. So, growers should be watching for symptoms of the disease which can be mistaken for nutritional deficiencies or abiotic disorders.
Pallidosis-related decline of strawberry is a viral disease caused by Strawberry pallidosis associated virus(SPaV) or Beet pseudo yellow virus(BPYV) along with non-whitefly transmitted viruses. Disease is not caused by SPaV or BPYV alone, but by the infection of SPaV or BPYV along with any of several non-whitefly transmitted viruses.
Symptoms of the disease include stunted plant growth, purple to red foliage, and brittle roots with reduced rootlets. Disease causes severe yield loss.
Whiteflies can cause a significant reduction in strawberry yield through direct feeding and indirectly through sooty mold and as viral disease vectors.
Biology: Greenhouse whitefly is about 1 mm long and has four membranous wings with white, powdery wax coating. Wings are held parallel to the top of the body. Eggs are small, elongated and attached to the lower leaf surface with a short pedicel. They are pale yellowish green to brown and turn dark with maturity. Eggs hatch and go through four nymphal instars before becoming adults. Immatures are oval, flat and often semitransparent. First instars are called crawlers which move around in search of ideal feeding sites on the underside of leaves. Later nymphal stages are immobile. Fourth instar nymphs are called pupa and have long, waxy lateral filaments and red eyes.
Management: Low population densities of whiteflies are usually controlled by the natural enemy complex in strawberries and pesticide treatments for other pests. Heavy infestations require timely treatments to prevent population build up. Monitor whitefly populations by using yellow sticky cards (1 per 10 acres) and counting their numbers on 20 mid-tier leaflets per each quarter of the field.
Refer to http://www.ipm.ucdavis.edu/PMG/r734301011.html for additional details on greenhouse whiteflies and their management.
My field trials: Among the control options that I evaluated, spiromesifen (Oberon) provided good control in a 2009 trial. In my 2012 large plot field trial, acetamiprid (Assail) alone at full label rate and acetamiprid at half the label rate along with the entomopathogenic fungus, Beauveria bassiana (BotaniGard 22 WP) provided a better control than other treatments.
2009 Trial: Percent change in whitefly populations two weeks after the treatment. *Note that spirotetramat is not registered for strawberries.
2012 Trial: Average percent change in whitefly populations after three applications. There was a general decline in their numbers throughout the experiment.
- Author: Surendra Dara
Petals, sepals, and developing fruit damaged and darkened from freezing temperatures (Photos by Surendra Dara)
Fruit deformation as a result of low temperatures which affect pollination. Smaller achenes are formed and uneven development of the tissue around them results in misshapen fruit. Notice larger achenes in unaffected areas (Photo by Surendra Dara)
Unusual cold weather during the past few days is a concern for the strawberry growers. Second year crop and cultivars that produce early or late can influence the extent of impact experienced by the growers because injury depends on the stage of development.
Damage: Low temperatures could completely damage the flowers or injure developing fruit tissue resulting in misshapen fruit. Pollination is also affected if temperature drops below 60 oF (15 oC) during flowering. As a result, some achenes do not have a seed, remain small, and cause fruit distortion. Cold injury can also cause fruit with multiple tips. Distorted fruit from lygus bug damage have uniform sized achenes, but the achenes affected by cold injury are much smaller than those on unaffected parts of the fruit.
Protection: Sprinkler irrigation can protect the fruits from cold injury when there is no or low wind. Freezing water releases heat and protects the flowers and fruits as long as temperatures do not fall below 23 oF (-5 oC) on still nights or 25 oF (-4 oC) when wind speed is no more than 2 mph. If wind speed is more than 4 mph, sprinkler irrigation is not recommended. Sprinklers must be started before the temperatures drop to freezing levels and continued throughout that period.
The time to start irrigation for frost protection depends on the dew point. If the dew point is low, irrigation has to be started before the freezing temperature. The following table shows when irrigation should be commenced depending on the dew point.
|
Dew Point |
Temperature at which irrigation should start |
Dew Point |
Temperature at which irrigation should start |
|
32 oF (0.0 oC) |
32 oF (0.0 oC) |
23 oF (-5.0 oC) |
38 oF (3.3 oC) |
|
31 oF (-0.6 oC) |
33 oF (0.6 oC) |
22 oF (-5.6 oC) |
38 oF (3.3 oC) |
|
30 oF (-1.1 oC) |
34 oF (1.1 oC) |
21 oF (-6.1 oC) |
39 oF (3.9 oC) |
|
29 oF (-1.7 oC) |
34 oF (1.1 oC) |
20 oF (-6.7 oC) |
39 oF (3.9 oC) |
|
28 oF (-2.2 oC) |
35 oF (1.7 oC) |
19 oF (-7.2 oC) |
39 oF (3.9 oC) |
|
27 oF (-2.8 oC) |
35 oF (1.7 oC) |
18 oF (-7.8 oC) |
40 oF (4.4 oC) |
|
26 oF (-3.3 oC) |
36 oF (2.2 oC) |
17 oF (-8.3 oC) |
40 oF (4.4 oC) |
|
25 oF (-3.9 oC) |
37 oF (2.8 oC) |
16 oF (-8.9 oC) |
41 oF (5.0 oC) |
|
24 oF (-4.4 oC) |
37 oF (2.8 oC) |
15 oF (-9.4 oC) |
41 oF (5.0 oC) |
Water should be applied at 0.10-0.15 (0.25-0.4 cm) inches per hour through sprinklers to provide adequate protection. Discontinuing sprinkler irrigation during the frost period can cause more damage. If sprinkler equipment is in shortage, limit the area to be irrigated. Sprinkler irrigation to an upwind or uphill field may provide some protection to an adjacent field downwind or downhill.
Drip irrigation can also provide some protection by wetting 6-12 inch (15-30 cm) of soil before the frost period. Wet soil stores and releases more heat than the dry soil.
Reference
2008. Integrated pest management for strawberries. Second Edition. UC ANR Publication 3351.
- Author: Surendra Dara
Novaluron (Rimon 0.83 EC, Chemtura USA Corp, Middlebury, CT) is a popular insecticide used by the strawberry growers for managing nymphal stages of the lygus bug. It is an insect growth regulator that inhibits chitin synthesis and thus interferes with the growth and development of the immature stages. It is effective against egg, nymphal or larval stages. According to some earlier studies, Chemtura restricted the use of adjuvants with novaluron. This has been a concern for the growers especially when novaluron has to be tank mixed with other pesticides and adjuvants. Chemtura's request to amend the label to remove the adjuvant/surfactant statement has been approved by the Environmental Protection Agency (EPA). Growers will soon be able to use adjuvants with novaluron when the new label is ready.
Background about EPA's requirement of adjuvant studies
Unless an adjuvant is not supposed to be used with a pesticide, EPA' s Office of Pesticide Programs (OPP) requires inclusion of adjuvants in the field trials for registering pesticides. This is mainly because of the impact of adjuvants on the pesticide residue levels. Because of this impact, there was a concern in EPA to require new studies with adjuvants for products that were previously registered without the adjuvant data. Crop Life America, Chemical Distributors and Producers Association analyzed historical data from OPP and concluded that adjuvants increase the pesticide residues, but the inherent variability in pesticide residues is more than what is caused by the adjuvants. Based on these analyses, Health Effects Division and Chemistry Science Advisory Council decided not to require new studies with adjuvants for products previously registered without them. As a result when registrants ask for label amendments related to the adjuvant use, EPA would use the fast track process.
What is an agricultural adjuvant?
Adjuvants are substances used with pesticides to improve their efficacy by improving the formulation, atomization, or biological action. Adjuvants act as spreading or wetting agents which reduce foaming, drift, and droplet size and increase the pesticide deposition, retention, and absorption. Agricultural adjuvants are categorized based on the chemical class into surfactants, oils, acidifiers and buffers, fertilizer adjuvants, and others. There are some green adjuvants that are safe to the environment.
Based on how an adjuvant is produced and its impact on the environment, Beck et al (2012) provided a definition for green adjuvants. “According to the production-based approach, adjuvants are defined as green if they are manufactured using renewable raw materials as much as possible while making efficient use of energy, preferably renewable energy. According to the environmental impact approach, adjuvants are defined as green (1) if they have a low human and environmental impact, (2) if they do not increase active ingredient environmental mobility and/or toxicity to humans and non-target organisms, (3) if they do not increase the exposure to these active substances and (4) if they lower the impact of formulated pesticides by enhancing the performance of active ingredients, thus potentially lowering the required dosage of active ingredients.”
References
Beck, B., W. Steurbaut, and P. Spanoghe. 2012. How to define green adjuvants. Pest. Manag. Sci. 68: 1107-1110.
Grains Research and Development Corporation. 2012. Adjuvants – oils, surfactants and other additives for farm chemicals – revised 2012 edition. Australian Government.
Ishaaya, I., S. Yablonski, Z. Mendelson, Y. Mansour , and A. R. Horowitz. 1996. Novaluron (MCW-275), a novel benzoyl urea, suppressing developing stages of Lepidopteran, whitefly and leafminer pests. pp. 1013-1020. In: Brighton Crop Protection Conf., Pests & Diseases, The British Crop Protection Council.
Martin, D. E., J. D. Lopez, Jr., Y. Lan, B. K. Fritz., W. C. Hoffmann, and S. E. Duke. 2010. Novaluron as an ovicide for bollworm on cotton: deposition and efficacy of field-scale aerial applications. J. Cotton Sci. 14: 99-106.
Spanoghe P, M. De Schampheleire, P. Van derMeeren, W. Steurbaut. 2007. Influence of agricultural adjuvants on droplet spectra. Pest. Manag. Sci. 63: 4–16.
