Joanne Whalen, Extension IPM Specialist; jwhalen@udel.edu
NOTE – Be sure to check BLT catches in your area for corn borer and corn earworm catches – we are seeing a significant increase in trap catches for both insect pests (http://ag.udel.edu/extension/IPM/traps/latestblt.html). On Friday, trap catches will be updated in the afternoon on the webpage.
Cabbage
Continue to sample for cabbage looper, diamondback larvae and harlequin bug. Although the pyrethroids will provide control of harlequin bugs, they are not effective on diamondback in our area. So 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. With the significant increase in corn earworm moth catches, moths can be readily found laying eggs in fields. Be sure to sample for corn earworm larvae as soon as pin pods are present. A treatment will be needed if you find one corn earworm larvae per 6 ft-of-row.
Melons
We continue to see an increase in aphid populations. Treatments should be applied before populations explode and leaf curling occurs. Lannate, Fulfill, Beleaf, Thionex, and Assail are all labeled for aphid control in melons. Be sure to check labels for the days between last application and harvest (PHI).
Peppers
We are seeing a significant increase in both corn earworm and corn borer moth catches in blacklight traps throughout the state. So be sure to maintain a 5 to 7-day schedule on all peppers for worm control. Be sure to check local moth catches in your area by calling the Crop Pest Hotline (in state: 1-800-345-7544; out of state: 302-831-8851) or visiting our website at (http://ag.udel.edu/extension/IPM/traps/latestblt.html). Also, be sure to select materials that control both earworms and corn borers.
Snap Beans
With the significant increase in both 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, it will not provide effective corn earworm control in processing snap beans. 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
As the earliest planted spinach emerges from the ground, 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.
EXTRA (added 8-25-08) It should 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 per 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. The first silk sprays will be needed as soon as ear shanks are visible. Be sure to check both blacklight and pheromone trap catches for silk spray schedules since the spray schedules can quickly change. Trap catches are generally updated on Tuesday and Friday mornings (http://ag.udel.edu/extension/IPM/traps/latestblt.html and http://ag.udel.edu/extension/IPM/thresh/silkspraythresh.html). You can also call the Crop Pest Hotline (in state: 1-800-345-7544; out of state: 302-831-8851). At this time of year, you will need to combine a fall armyworm material with a pyrethroid for the first 2 to 3 silk sprays for fall armyworm control. Be sure to check all labels for days to harvest and maximum amount allowed per acre.