Yesterday I had the pleasure of attending the Sustainable/Organic Insect Management for Vegetable Growers Workshop in Clinton, SC. Our first stop was Parson Produce, a certified organic farm located at Bush River Farm.
Here we were greeted by Daniel Parson, a young and gregarious farmer who has been farming for 12 years. Daniel is a great presenter and has a Master's degree from Clemson University. Some of you may know Daniel from his presentations at SSAWG.
Daniel discussed his farm and showed us his farming equipment, which he stated is a piece of his pest management strategy. In true organic fashion, his production is a whole-farm system and pest management starts with productive soils, adequate not abundant nutrition, cover crops and good weed management.
Next, we moved to the field where Dr. Powell Smith (Extension entomologist and vegetable specialist from Clemson University) showed us some insect collection tools. These include sweep and butterfly nets, aspirators (used for catching small insects by sucking them into a container) and fabric sheets.
Below you can see Daniel's cover crop mixture of sorghum-sudangrass and buckwheat.
A great place to find insects!
Check out this field of pure buckwheat! A quick summer cover crop and insect attractor.
Insects, especially those that are predators to some plant-eating insects love the small buckwheat flower and will visit often for a source of food.
Daniel allows his buckwheat to go to seed and therefore re-seed the field.
Here is a group of workshop participants learning about the insects they collected in the buckwheat.
Next, we moved on to look at the broccoli to see what kind of insects we could find in this crop.
Here we saw some bad insects, but also some natural predators. We also learned about 'banker plants'. 'Banker plants' are plants that have some kind of problem and attract crop destroying insects and the predators that feed on them. Daniel has chosen to leave his 'banker plants' in order to keep the good insects in the planting. His 'banker plants' had lots of aphids (typically a sign of excess nitrogen). In addition to the aphids, they contained aphid predators. Below is a lady beetle larva feeding on the aphids.
Syrphid fly larvae were also present and feeding on the aphids(below). These insects are known as "aphid killers".
We also found harlequin bugs, a yearly problem on brassica crops. Below are nymphs of the piercing/sucking pest.
Exploring the eggplant crop we noticed a lot of flea beetle damage. Management for flea beetles is difficult. Some have found that row covers are effective for crops that do not require pollination. The covers cannot have open spaces for the beetles to enter. This control method is not effective if the flea beetle larvae are present in your soil. If they are, you will be trapping them in and may have a big problem on your hands.
Below you can see some flea beetle damage (the shot holes). The insect pictured below is an adult two-lined spittlebug, which is a plant-feeding insect.
Another plant-feeding pest that we found on the eggplant was a some kind of leaf-footed bug (below).
Thrips damage was also noted on the eggplant crop. Thrips are usually found in the flower of crops. These insects have rasping mouthparts. Damage on eggplant appears as green to brown streaking on the fruit. Sorry, I don't have a picture.
After all of our fun in the field, we enjoyed a delicious lunch prepared by the owners of Bush River Farm and Bed and Breakfast.
After lunch the group headed to Presbyterian College to learn some more about insect pest management and to do some more insect identification. Dr. Powell Smith discussed the different characteristics of identifying insects and the major plant-feeding and beneficial insect groups. The group discussed management options and the importance of attracting beneficial insects, as well as learning about the life cycle of an insect pest.
Overall, managing insects in vegetable crops organically is similar to a conventional IPM approach. Like discussed above, healthy soils, adequate nutrition and weed management will go along way. IPM includes cultural control methods (including proper selection of vegetable varieties for your area, avoiding insects by changing planting date, eliminating insect overwintering areas, attracting beneficial insects, planting trap crops, etc), using mechanical or physical control methods (tillage to disturb life cycle, row covers, hand picking or vacuuming) and finally the use of organically approved insecticides. Keep in mind that many insecticides will also kill or disturb your beneficial insects, that is why it is your last line of defense.
To learn more about attracting beneficial insects and biological control, visit NCSU's Biological Control Information Center or the Biological Control Resources page on GrowingSmallFarms.org.
Overall, the day was successful. We learned a lot about identifying insects, management options and even got to take a few specimen home with us. Below you can see our insect collection.
I took a wheel bug (a predator in the assassin bug family), a leaf-footed bug and larva, a squash bug and a running ground beetle (a voracious eater in the Carabidae that will feed on cutworms) home with me!
To learn more about insect identification, insect collection and insect control visit the following links:
ATTRA's Links to Insect Management
Growing Small Farms Links to Insect Management Web Resources
Collecting and Preserving Insects and Arachnids