By Josie Borlongan, Garden Guides Contributor
Pickleworms (Diaphania nitidalis) are the larvae of night-flying moths. They seek out tender growing tips on young plants to feed on. Once they become caterpillars, they then switch to eating flowers and fruits. These garden pests are predominant in the southeastern United States, ranging north to Connecticut and New York. They overwinter only in Florida and Texas, where they may be active all year round.
Pickleworms have very short lifecycle, lasting as little as 3 weeks. After feeding for about 2 weeks, the larva spins a cocoon in a rolled section of a leaf. The pupa rests for 7 to 10 days, and then the new moth emerges to start another generation.
Prevention and Control
Choose resistant varieties of susceptible crops. Also plant fast-maturing varieties as early as possible in spring to promote strong growth and fruit set before pickleworms reach damaging levels.
Cover seedbeds and young plants with row cover and seal edges to prevent moths from laying eggs on plants. Keep the cover for as long as possible.
A single caterpillar can tunnel into and ruin the plant's leaves, flowers and fruits.
Nematodes, Parasitic wasps, Assassin bugs, Lacewing, Minute pirate bugs, Bacteria (Bacillus thuringiensis, Saccharopolyspora spinosa), Trichogramma wasps
Spraying flowers with beneficial nematodes once a week is helpful, because the nematodes can survive in the damp enclosed areas of the flowers and attack pickleworms feeding there.
Use of bacterial sprays (Bacillus thuringiensis, Saccharopolyspora spinosa) can also kill pickleworms if they eat the treated flowers and leaves. These sprays cannot kill pickleworms burrowing in fruits and stems.
Other Methods of Control
* Trap Crops. Plant summer squash a week or two ahead of desired crops. Check growing tips and flowers of the trap crop daily for pickleworms. Kill any caterpillars that you may see. When the blossoms get infested, destroy the trap crop and then plant a new hill of summer squash and repeat the process of killing caterpillars and destroying trap crops.
* Insect Traps. During the early part of the season, set up insect traps that include floral lure to attract pickleworm moths. Trapping female pickleworm moths will reduce the number of laid eggs.
* Garden Cleanup. After harvesting, shred all crop remains to kill hidden larvae. Work the soil to bury the pupae.