Extension Report

Baldwin County Extension Office

302A Byrne Street

Bay Minette, AL  36507

Telephone (251) 937-7176 or

928-0860/943-5611 ext. 2222

FAX (251) 937-7285

Dr. Ayanava Majumdar

Extension Entomologist & Sustainable Agriculture Project Coordinator

July 12, 2011

Stay Alert for Vegetable and Peanut Insect Pests!

Here are a few updates for vegetable and peanut producers based on the past few weeks of scouting. The first thing that came to my mind as I developed this article was the drought situation in Alabama which not only affects crop maturity but also insect development. There are some insect pests that are positively affected by a drought (for example, grasshoppers and lesser cornstalk borers) while the majority of insects are inhibited by high temperatures (for example, caterpillars, aphids). Note that the presence of a high number of predatory insects such as lady beetles and lacewings is facilitated by milder temperatures and availability of food. Readers interested in learning about pest and beneficial insects should attend one of the many integrated pest management (IPM) field days being organized this month across Alabama.

Squash bugs were incredibly high very early this year leading to a lot of frustration among conventional and organic producers. While pyrethrin and neem work well against squash bugs in organic system, several synthetic pyrethroids like cyfluthrin, bifenthrin, and lambda-cyhalothrin work well in conventional cropping system. Stink bugs have been worse this year than 2010 and we are noticing heavy speckling damage (semi-ripened tomatoes) in research plots at Fairhope, AL. Aphids are abundant on okra plants that were planted as a perimeter trap crop in demonstration plots (Figure 1). Since our battle against sucking pests has just begun, the management approach has to be broad based for long-term benefits. Some management tactics for controlling sucking insect pests include increasing plant diversity, planting resistant varieties, incorporating some mechanical control tactics (row covers or insect netting), trap cropping (luring insects away from main crop) and by rotating insecticides sequentially.

After the squash bug invasion is over, squash vine borers seem to take down any remaining squash vines. Squash vine borer is a clear-winged moth that hovers at the base of plants like a wasp. The female lays eggs at the plant base and the larva is difficult to control once it enters the plant. It is highly recommended that squash producers monitor the vine borer moth activity using pheromone traps. To watch a video on pheromone trap-based scouting system for vine borers click http://tinyurl.com/3s2efkv. On a small scale, vine de-worming that is physical removal of borer from plant stems may also work; to learn more watch the video http://tinyurl.com/3oy2487. Producers can use a flexible plant collar made from insect netting wrapped around the base of plants to deter egg laying by female moths. Plant rotation and resistant varieties are also effective in reducing vine borers. 

Fall and beet armyworm moth numbers are slowly rising in insect traps indicating increasing mating and egg laying activities. Fall armyworm outbreaks are being reported from central and northeast Alabama in pasture fields but the future generations of armyworms could show up on tomatoes, peanuts, okra and other attractive host plants. Beet armyworm numbers are ahead of the fall armyworms and this is usually the case every year. Beet armyworm is a major vegetable insect pest in the southern counties and chemicals like methoxyfenozide (insect growth regulator called Intrepid) and flubendiamide (insect feeding inhibitor called Synapse or Belt) provide effective control. Organic producers can use spinosad (Entrust), Bt, and Spod-X for beet armyworm control (remember to rotate insecticide to avoid resistance). Bt and Spod-X are living insecticide with a broad spectrum of action; these formulations should be applied to lower parts of the leaf and in protected places in order to extend the life of the product. Do not apply the insecticides on the top of the leaves on a hot afternoon since the living cells die within few minutes under such conditions. Although tomato fruitworms and hornworms are visible on vegetables, there seems to be a very weak association between moth numbers in traps and actual caterpillar numbers (this anomaly is probably due to weather fluctuation and drought). For more control recommendations, garden vegetable and organic producers should refer to the updated pest management bulletin available at http://www.aces.edu/go/171. Commercial vegetable producers should use the Southeast Vegetable Crop Handbook available at http://tinyurl.com/3b5pfsq.

Here are some updates for peanut producers in the region. I have got two calls about peanut burrowing bugs and I am sure there are more burrowing bug infested fields if the producers looked really hard. This insect appears to be an increasing problem in peanuts grown on conservation tillage land (with a high crop residue on soil surface) and insect infestations could get out of hand if proper crop rotation is not followed. Peanut burrowing bugs are small actively crawling insects with spiny legs and semi-hardened wings. The nymphs and adults have piercing and sucking mouthparts, and follow the soil cracks to move between plants. The feeding damage is seen as pitting on pegs and pods. Also watch out for the lesser cornstalk borer in hot dry areas. Typically, the lesser cornstalk borer activity peaks in late-July. Drought enhances damage to peanuts and caterpillars can be seen living in silken tubes attached to the stems, leaves, and developing pegs. Insecticide like chlorpyrifos is effective against soil pests of peanuts but must be applied in a timely manner. Granular insecticides can be ineffective in hot dry condition as the product will just sit on top of the soil and will not get activated to be effective.

Finally a reminder about Extension field training events. If you are interested in knowing more about trap cropping, net house vegetable production, irrigation methods, and/or organic vegetable production practices, please participate in any of the three field days being organized by Alabama Cooperative Extension System and Tuskegee University. Field days will be on July 29th at the Gulf Coast Research and Extension Center, Fairhope, Alabama (to register call 251-937-7176), on July 28th at the Rural Heritage Center, Thomaston, Alabama (to register call 334-295-5959) and on July 27th at Jack-O-Lantern Farm, Muscle Shoals, Alabama (to register call 256-766-6223). Readers can also join the Alabama Vegetable IPM or the Alabama Peanut IPM Program pages on Facebook for receiving real-time pest updates.

Cell phone: 251-331-8416                                                                                         

E-mail: azm0024@aces.edu

Baldwin County Extension Programs are supported by the Baldwin County Commission.

The Alabama Cooperative Extension System (Alabama A&M and Auburn Universities) in cooperation with the U.S. Department of Agriculture is an equal opportunity educator and employer.