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Commercial Horticulture > Comm Hort Blog > Posts > Alabama Vegetable Insect Pest Scouting Report - June 29, 2015

Caterpillar alert: A detailed blog with statewide insect activity report and maps is available at https://goo.gl/a9b81q. Beet armyworm numbers have increased by 40% in the past weeks and now producers should be noticing caterpillars on various crops, if you are in an area of high insect pressure. Fall armyworm activity has increased about 50 to 60% statewide at monitored locations. Corn earworm, tobacco budworms, and soybean looper activity is still low across the state – but activity may increase dramatically with rising heat levels in July and August. Squash vine borer activity has been incredibly high at about 50% of the monitored locations for the past several weeks – populations are decreasing now since there is only one flight of the moths.

Conventional caterpillar management: Full insecticide recommendations can be found in the SE Vegetable Crop Handbook (http://goo.gl/Tm14aW). There are many synthetic pyrethroids that are very effective against caterpillars (e.g., products containing zeta-cypermethrin, lambda cyhalothrin, and bifenthrin are very effective). These insecticides also give excellent control of stink bugs and leaffooted bugs (we use them on our sorghum trap crops to kill 90% leaffooted bugs).
CAUTION – do not overuse synthetic pyrethroids in hot summer months as it will flare up spider mites (they are worse than caterpillars and other foliar pests taken together!). We stop spraying our research and demonstration plots immediately after the populations crash and let the natural enemies do their work.
 
Other EXCELLENT caterpillar control insecticides include chlorantraniliprole (Coragen), Belt (flubendiamide), and Radiant (spinetoram). These insecticides are very useful pest prevention products, have longer residual, and can be used with reduced chance of secondary pest issues. They are also softer on many natural enemies, which is a benefit in the long run. All the three products mentioned have done great in tomato IPM trials in Alabama. Due to selective nature of these products, you may have to resort to the use of pyrethroids for controlling sucking insect pests.
 
Organic caterpillar management: If you can keep the moths away from the crop, then that goes a long way in reducing egg and caterpillar pressure on the crop. High tunnel crop producers and gardeners can read the pest exclusion system at http://www.aces.edu/anr/ipm/Vegetable/pestexclusion.php (download the SARE Bulletin from the website). Organic pest management recommendations can be found in the Alternative Vegeatable IPM Slide Chart which is a handy tool for producers and gardeners. Bt products like Xentari and Dipel work great when pressures are lower and regular weekly spray applications can prevent caterpillar outbreak. Bt products are selective organic insecticides and do not affect the natural enemies. A tank mix of Xentari and Pyganic is effective against armyworms. Entrust (spinosad) is the expensive but the last option for caterpillar control when the risk of crop failure is high. Stop insecticide use when the population is under check and let the natural enemies do their work.
 
Sucking insect pests: So far we have seen a few leaffooted bugs and stink bugs on various crops. We have seen a lot of squash bugs and egg masses on our Hubbard squash trap crops in Clanton and Cullman. Baby Blue and New England Hubbard squash have the remarkable property of attracting and retaining squash bugs and cucumber beetles; this prevents insect outbreaks on yellow squash (main crops of Destiny or Prelude). We are letting the squash bugs and cucumber beetles buildup for few more days and then we will kill them with insecticides to prevent pest migration. We will be testing conventional and organic insecticides at these trap crop locations to manage pests. For sucking insect pest management, refer to the SE Vegetable Crop Handbook.
 squash bug nymphs 6-29-15.JPG

Organic sucking insect pest control means “thinking outside the box” since none of the approved insecticides work very well against the adults or last very long in open field conditions. High tunnel producers may have a better luck at stopping the adult bugs with the pest exclusion system described earlier (download the SARE bulletin from http://goo.gl/epfef3). We continue to evaluate organic insecticides on trap crops to target the early immature stages which may lead to better success.
 
Cowpea curculio (photo below) is active on late-planted southern peas in Headland, AL (research plots). This pest is resistant to synthetic pyrethroid insecticides, so cultural control tactics are the best way to manage this insect in the long-term. There are some reports of insecticide-based suppression of curculios in peas, but the chemicals have to be applied ahead of pest migration to the crop. For more information, please call 251-331-8416 or email bugdoctor@auburn.edu.
 cowpea curculio 6-29-15.JPG
Other useful resources for producers:
Vegetable IPM website www.aces.edu/vegetableipm  
Facebook page: Alabama Vegetable IPM
Alabama IPM Communicator e-newsletter: www.aces.edu/ipmcommunicator
 
Ayanava Majumdar, Ext. Entomologist

 


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