Joanne Whalen, Extension IPM Specialist; jwhalen@udel.edu
Cabbage
Continue to sample for cabbage looper, diamondback larvae and harlequin bug. Be sure to scout and select control options based on the complex of insects present in the field.
Cucumbers
Be sure to watch for an increase in cucumber beetle and aphid populations. A treatment should be applied for aphids if 10 to 20 percent of the plants are infested with aphids with 5 or more aphids per leaf.
Lima Beans
Continue to scout for stinkbugs, lygus bugs and corn eaworm. Economic levels of stinkbugs and earworms can be found. Since trap catches remain high, multiple applications may be needed for earworm control. At this time of year, we have also found soybean loopers in lima bean fields. If soybean loopers become a problem again this year, remember that they are a migratory pest, difficult to control and pyrethroid resistance has been documented in states to our south. Therefore, you will need to consider an application of Lannate LV at the higher rate for soybean looper control. The following is the link to the Lannate label (http://www.cdms.net/LDat/ld183010.pdf). Be sure check the label for rates and days from last application to harvest.
Peppers
With the high corn earworm and corn borer moth catches in blacklight traps throughout the state, be sure to maintain a 5 to 7-day schedule on all peppers for worm control. Also, be sure to select materials that control both earworms and corn borers.
Snap Beans
With the high corn borer and corn earworm moth catches, you will need to consider a treatment for both insect pests. Sprays are needed at the bud and pin stages on processing beans for corn borer and corn earworm control at this time. As a reminder, if you are using Orthene (acephate) for corn borer control in processing snap beans, it will not provide effective corn earworm control. You will need to combine Orthene with a corn earworm material (e.g. a pyrethroid) or use a material that will control both insect pests. Check our website for the most recent trap catches in your area to help decide on the spray interval between the pin stage and harvest for processing snap beans (http://ag.udel.edu/extension/IPM/traps/latestblt.html and http://ag.udel.edu/extension/IPM/thresh/snapbeanecbthresh.html).
Spinach
Be sure to watch for webworms and beet armyworms. Both moths are active at this time and controls need to be applied when worms are small and before they have moved deep into the hearts of the plants. Also, remember that both insects can produce webbing on the plants. Generally, at least 2 applications are needed to achieve control of webworms and beet armyworm. It should also be noted that the rates listed in the Vegetable Recommendation Guide for Avaunt on spinach are not correct. The maximum use rate on spinach is 3.5 oz/acre. The rates listed in the book are for other leafy greens. As always, be sure to check the label for use rates and restrictions. Here is the link to the label (http://www.cdms.net/LDat/ld4BD004.pdf).
Sweet Corn
With the high corn earworm catches throughout the state, all fresh market silking sweet corn should be sprayed on a 2-day schedule.