Question of the Week
Answer: Thank you for your recent request for information from ATTRA, the National Sustainable Agriculture Information Service regarding organically approved management alternatives for “pickleworm.”
Pickleworm is a tropical insect and is known to invade much of the southeast U.S. each summer. It is a moth that has made cucumber and squash production in many areas of the south prohibitive without extensive chemical use. Although cucumbers are severely damaged some years, squash appears to be the preferred and favorite host. Squash flowers, fruit and small plants become heavily infested while adjacent cucumber flowers and fruit may remain clean.
Resistant varieties of squash are Butternut 23, Summer Crookneck, Early Prolific Straightneck, and Early Yellow Summer Crookneck. The more susceptible varieties are Cozini, Black Zucchini Caserta, Zucchini, Shrot Cofozella and Benning Green Tint Scallop. Many other varieties tested fall between these groups. Tests with insecticides show much better control of pickleworms on resistant varieties than on susceptible varieties. Cucumbers, cantaloupes and watermelons are less frequently and less destructively attacked than squash.
A few plants of a susceptible squash variety are helpful in detecting the first appearance of pickleworms, as evidenced by the insect's presence on flowers. A regional and state pickleworm surveillance program using squash as a trap crop or a sex pheromone trap throughout the Southeast is in various stages of development. You might want to check with you local Extension service to see if they have a similar program in Hawaii.
Natural enemies such as generalist predators and specific parasitoids have occured elsewhere, but have not reliably suppressed damage (Capinera 2000). In Hawaii, no parasitoids have been discovered for pickleworm, although predators such as lacewings have been observed attacking pickleworm caterpillars.
Insecticide applications should begin immediately when pickleworms or their damage appears. Make applications at weekly intervals. More frequent applications may be needed if populations and temperatures are high.
Some organically approved products that are listed on the ATTRA Biorationals Database include:
Neemix 4.5—a botanical pesticide extracted from the Neem tree. The active ingredient is Azadirachtin which is a insect growth regulator. It kills/repels a variety of insect pests including whiteflies, caterpillars, leafminers, aphids, and diamondback moths.
These two active ingredients are derived from the oil found in neem tree seeds. Humans have used this naturally-occurring oil for millennia for medicinal, cosmetic, and pesticidal purposes. When used in pesticide products, both azadirachtin and clarified hydrophobic extract of neem oil can be applied to many food and non-food crops indoors and outdoors to control certain insects and related pests. Adverse effects are not expected to humans, wildlife, or the environment when products containing these active ingredients are used according to label directions. Labels direct users not to contaminate water and not to apply when honeybees are actively visiting flowers in the area. Disrupts insect molting by antagonizing the insect hormone ecdysone; Also serves as feeding deterrent for some insects
Entrust is a biorational pesticide that is OMRI Listed. It is a fermentation-derived insecticide which controls Lepidoptera, Diptera, Thysanoptera, and some Coleoptera. It is available from many organic suppliers, such as Peaceful Valley Supplies and Organic Growers Supply (see below for contact information.)
Condor is a biological insecticide from the Bacillus thuringiensis var. kurstaki for the control of lepidopteran pests. Bacillus thuringiensis delta endotoxins encapsulated in killed Pseudomonas fluorescens control insect larvae on a wide range of crops. Insect larvae vary in how susceptible they are to the many different Bt endotoxin proteins, but Condor is labeled for management of pickleworm.
I also came across some research on using Effective Micro-organisms (EM) to manage pickleworm, although, mind you, the research was done by EM distributors. I have referenced a summary of their research, for you to judge if this would work in your situation.
I always encourage organic growers to employ a combination of treatments to manage particularly pesky pests. This may be necessary with the pickleworm in your tropical climate. Also check with your certifier to insure that these products are allowable under their program. Neemix and Entrust are OMRI certified.
Wood, Matthew, et al. (no date). EM-Fermented Plant Extract and EM5 for Contolling Pickleworm in Organic Cucumbers. Sustainable Community Development, LLC.
Capinera, J. L., 2000. Featured Creatures: Pickleworm. Publication EENY-164. University of Florida, Institute of Food and Agricultural Sciences.
Heu, Ronald, et al. 2005. Pest Advisory Report: Pickleworm. State of Hawaii, Department of Agriculture.
Peaceful Valley Farm Supply
P.O. Box 2209, 125 Clydesdale Court
Grass Valley, CA 95945
Order Toll Free (888) 784-1722
Organic Growers Supply Catalog
PO Box 520
Waterville, ME 04903
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