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Whether you are a conventional or an organic vegetable producer, an integrated pest management or IPM strategy for the modern farm includes a multi-faceted approach consisting of pest prevention and control strategies that aim at reducing pest populations below threshold levels. Proper pest identification and scouting are critical initial steps that form the basis of a proper IPM practice. Indiscriminate use of conventional or organic insecticides have resulted in many cases of insecticide resistance. Cultural control as well as pest exclusion systems suitable for small and large operations are prevention tactics, while insecticides should always be the last resort. Since many organic insecticides are low-persistence products designed to be environmentally friendly, there are additional benefits to evaluating the synergistic effects of rotations and tank-mixes for controlling insect pests. We encourage producers to do their own on-farm tests to gain experience in using new premix insecticides or rotations according to the insecticide label. Growers should keep good spray records and compare multi-year observations for developing a long-term IPM plan.

 

Organic insecticide rotations with single active ingredient (AI) and premixes:

  • When dealing with some tough insect pests, organic insecticide rotation can be critical compared to repeated applications of a single AI. Proper insecticide rotation can reduce cost by reducing the application frequency of expensive products and target multiple species.
  • Typically, we have seen a good insect control by alternating selective insecticides with a broad-spectrum product. Always check the need for additional spray applications to reduce undesirable environmental effects. Incorporating selective insecticides in a rotation schedule encourages natural enemy populations to rebound after using harsher products. For example, in leafy brassicas, using Bt products first is a good strategy when population pressure is low. Later applications can include pyganic or spinosad based products (e.g., Monterey Garden Insect Spray). Three to four alternating applications can provide significant cabbageworm, looper, and diamondback moth control in open field or high tunnel crops.  
  • If you have yellowmargined leaf beetles on brassicas, then early application of pyrethrin, spinosad or premix products such as Azera (neem + pyrethrins, Valent USA) or Botanigard Maxx (Beauveria bassiana insect pathogenic fungus + pyrethrins, BioWorks) are good options. As caterpillar pressure rises through the season, Bt-based insecticides can be part of the rotation.
  • In tomatoes and other summer crops, Bt-Pyganic or Bt-Azera rotations also improved plant stands compared to the untreated check, indicating successful caterpillar control in the early season that generally resulted in higher crop production levels later.

 

Few pointers for vegetable growers:

  • Use surfactants on leafy vegetables with a wax layer to increase insecticide retention on or below the leaf surface where insects hide. Some organic surfactants include SKH Sticker, Ag Aide and EcoSpreader (Brandt, Inc.). Check insecticide label before mixing a spreader/sticker for compatibility issues; when in doubt, use the spray mixture in a small area before treating large fields. 
  • Benefits from tank-mixes and rotations may occur after 3 to 4 applications with weekly assessment of pest population levels (need-based applications). Tank-mixes should not be used for pest "prevention" as that may result in the target pest becoming resistant to two products simultaneously and wipe out the natural enemies leading to new pest problems.  
  • Use caution while spraying pyrethrin and spinosad products around beneficial insects. While these products are organic, they are toxic to pollinators. Avoid spraying when winds are high, or when pollinators are active.

 

Sources of organic insecticides:  Always check the insecticide label on the manufacturer's website before purchase. Many single or premix insecticides are available from online retailers that include Arbico Organics, Gardens Alive, Seven Springs Farm, Forestry Distributing, Amazon, and many others. Make sure to check the expiration date on the package and product quality before mixing. Consult product labels for primary tank-mixing instructions. Do not store insecticide mixes in spray tank to prevent corrosion. Wash application equipment thoroughly after use to prevent cross-contamination and accidental crop damage due to misapplication. When in doubt, call the manufacturer and/or the retailer for product details.   

 

Use the New Organic Vegetable IPM Toolkit Slide Chart

A revised Organic Vegetable IPM Toolkit is now available for natural and organic farmers. This rectangular slide chart has sustainable IPM recommendations for over 20 major vegetable insect pest species and is a good starting point for beginning or transitioning growers. For a free copy, please email bugdoctor@auburn.edu, contact a commercial horticulture regional extension agent, or attend a beginning farmer workshop in Alabama. Funding for this IPM toolkit was provided by the USDA SARE, BFRD, and Specialty Crops Block Grant Programs. 

 

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Funding: The research and educational activities were funded by various USDA-NIFA and Alabama Department of Agriculture and Industries grant programs. Educational activities are carried out in an unbiased manner to benefit all producers across the state and the southeast.  

Ayanava Majumdar,

Extension Entomologist and

SARE Program Coordinator, Auburn University

 

Gary Gray and Sam Boring,

Regional Extension Agents


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