caterpillars

Questions About Biological Worm Spray (Bacillus thuringiensis var. kurstaki)

~ illbtru ~ 6 Comments

I get many questions regarding the use of biological caterpillar (worm) spray. There are many misconceptions about how this valuable tool is used. Let’s clear the air! Bacillus thuringiensis var. kurstaki or Bt was discovered back in 1901. The name of the bacteria was given in 1911. I’ll not bore you with the rest of the history.

Suffice it to say, due to the use of synthetic pesticides, many were concerned about the toxicity and environmental issues. Fast forward to the 1980s. Bt became essential as an alternative to toxic pesticides. The effectiveness of Bt is remarkable to say the least. The bacteria with its crystalline toxins attack the gut of caterpillars and destroy the creature from within. When used on a frequent basis, it is almost 100% effective. It is totally safe for humans, pets, birds, fish, pollinators and beneficial insects. Bt may be sprayed up until the time of harvest!! Bt is no longer viable or effective after continued exposure to ultra-violet light and water.

The greatest misconception involves the insertion of the Bt genetic material into the seed germ. The Bt GMO* ready corn or potatoes has Bt as an internal mechanism to kill caterpillars. The agri-business companies use other genetic materials (from other bacteria and viruses) to potentiate the Bt gene. This really is scary stuff!!!

The externally sprayed Bt material is completely safe. It is not systemically part of the plant. Whereas, a Bt GMO* ready crop has the insecticide in all parts of the plant. This GMO creation was made for convenience and to save money. No one can say for sure what are the long term effects!!!

I started using Bt in 1978. Up until that time, my broccoli plants were full of caterpillars. I remember being served some broccoli, only to find dead worms on my plate. Ugh, nasty! Once I used Bt, there were no more worms!!! It really does work!! Plus, it is very cost effective and safe to the environment.

*GMO – Genetically Modified Organism – “A GMO is a plant or animal that has been genetically modified through the addition of a small amount of genetic material from other organisms through molecular techniques. Currently, the GMOs on the market today have been given genetic traits to provide protection from pests, tolerance to pesticides, or improve its quality. Examples of GMO field crops include Bt-potatoes, Bt-corn, Bt-sweet corn, Roundup Ready soybeans, Roundup Ready Corn, and Liberty Link corn.” University of Kentucky Entomology

Papa

What do I do with the worms on my Korean red eggplant?

~ illbtru ~ Leave a comment

What shall I do about inch worms of the tiniest size eating my Korean red eggplant ? There doing quite a job at eating big holes? Thanks Art

Pandora

Pandora,

Visit your local garden center and purchase Dipel or Thuricide.

DiPel® is a biological insecticide containing the naturally occurring microorganism Bacillus thuringiensis subspecies kurstaki(Btk) DiPel is more specific in its spectrum of insect toxicity against caterpillars.

Thuricide BT Caterpillar Control concentrate is used by organic gardeners and is made from bacteria that is toxic to listed pests. Safe to use on all plants, vegetables and edible crops. Thuricide is a biological insecticide with Bacillus thuringiensis (Bt) for use on fruits, vegetables, shade trees, and ornamental plants to treat a variety of leaf-feeding worms. Pests treated include bagworms, tent caterpillars, gypsy moths, cabbage loopers, and tomato hornworms .

Follow the label instructions and apply with a sprayer. The Bt spores  maximize efficacy against lepidopteran pests.

Days to Harvest: There are no restrictions on applying DiPel or Thuricide up to the time of harvest.  DiPel or Thuricide  may be used for any labeled pest and  an insecticide for use against listed caterpillars (larvae) of  lepidopterous insects. Close scouting and early attention to infestations is highly recommended. Larva must eat deposits of DiPel or Thuricide to be affected.   • Treat when larvae are young (early instars) before the crop is damaged. • Larvae must be actively feeding on treated, exposed plant surfaces. • Thorough spray coverage is needed to provide a uniform deposit of DiPel or Thuricide at the site of larval feeding. Use overhead spraying to obtain good spray coverage on both sides of foliage. Use sufficient spray volume to insure uniform deposition on all plant surfaces. • Under heavy pest population pressure, use the higher label rates, shorten the spray interval, and/or raise spray volume to improve spray coverage. • Repeat applications at an interval sufficient to maintain control, usually 3 to 14 days depending on plant growth rate, moth activity, rainfall after treating, and other factors. If attempting to control a pest with a single spray, make the treatment when egg hatch is essentially complete, but before crop damage occurs. • A spreader-sticker which has been approved for use on growing and harvested crops should be added for hard-to-wet crops such as cabbage, or to improve weather-fastness of the spray deposits.

Let me know how this works for your eggplant. Watch for butterfly and moth activity as this will help you monitor the impact on your eggplant.

Art