Message #245 - THE_HERBALIST Date: 03-05-96 01:25 From: Trav'ler To: ALL Subject: Worm Control Pt1 of 2 ------------------------------------------------------------------------------- Copied from: Texas Agriculture Extension Service _Texas Earth-Kind (tm) Landscape and Gardening Guidelines_ Spring 1996 ***********************< Start Text >************************** BT - Worm Control People are afraid of pesticides! People should be "respectful" when using pesticides because, obviously, *they are poisonous*. If they weren't, pesticides would not kill bugs! Yet people still want to rid their plant life of creeping, crawling critters called worms (which are actually insect larvae) that devour plants day and night. Good News! There is a pesticide available which kills worms but is not harmful to man or beast. The worm killer is the bacteria _Bacillus thuringiensis_ or B.T. for short. When ingested, B.T. produces within its victims, a toxic substance. Only certain species of caterpillars are affected by B.T. The infection only occurs when the caterpillars feed on desirable plant foliage which is being protected by B.T. Adult insects which feed on plant nectar are not affected. So only the bad, destructive caterpillars are killed; the good bugs are spared. B.T. is not a merciful killer. Death is slow and painful. The first symptom experienced by a B.T. victim is "gut" paralysis. Of course, this means an immediate cessation of foliage eating which is a desirable result for the preservation of plants. But B.T. does not stop there. Eventually, B.T. causes a breakdown in the gut wall and leakage of contamination into the body cavity of the larvae (caterpillar victim). Since the body cavity tissues of a caterpillar are bathed by blood in an open circulatory system, the larval blood offers an ideal growing condition for growth of this contamination. B.T. contamination produces spores which divide rapidly. In fact, a new generation of spores are produced every 20 minutes. Therefore, after just 12 hours, one spore can produce 6,719,476,736 new B.T.'s. Obviously, this many new B.T.'s needing nourishment from the innards of a caterpillar soon has a devastating effect. B.T. is terminal. All larvae infected become sick and most die. This is because insects do not have an effective immunity system such as those in humans and other mammals. In theory, the lack of an effective immunity system dictates that the susceptible species will not develop a resistance to B.T. Outward symptoms of caterpillars infected by B.T. are manifested as behavior, color, and morphological changes. As soon as infected, larvae quit feeding. They usually move from their normal feeding sites to exposed leaf surfaces. Before dying, they become sluggish, discolored, and usually exhibit regurgitation and diarrhea. The cadavers of larvae become limp, but they do not "liquefy" as do viral-infected larvae. Cadavers of small larvae are often difficult to find because they turn black and become shriveled. Usually one taste of B.T. is enough to destroy susceptible larvae. However, in some instances, a larvae may not die from B.T. but suffer a fate worse than death. These include: - A predisposition to other natural occurring pathogens such as other bacteria, fungi, and viruses. - Starvation due to digestive tract disruption. - Failure to pupate due to physiological malfunctions. - An increases susceptibility to predators and parasites as a result of sluggish movement and migration to exposed leaf surfaces. - Increased sensitivity to harsh climatic factors such as high or low temperatures. - Reduced reproductive potential. Infected larvae that do successfully mature into adults are abnormally small and weak individuals. They are significantly less fertile than normal adults and incapable of successful mating. That alone is a fate worst than death! ___ Blue Wave/QWK v2.12 --- EzyQwk V1.10 00f9003b * Origin: The Dungeon, Anything is possible 210-674-4978 (93:9040/2) @PATH: 9040/2 0 9000/0 9004/0