Lecture 5

Question 1

what are pesticides?

Answer 1

Chemical compounds used in agriculture that act as sodium channel activators (DDT) or as acetylcholinesterase inhibitors (organophosphates), in both cases causing nervous hyperactivity leading to death.
However, these compounds are highly harmful to other animals due to bioaccumulation.

Question 2

DDT

Answer 2

Toxic, non-specific, generates resistance and has a high persistence in the environment.

Question 3

what are biopesticides?

Answer 3

biopesticides are natural compounds with lower toxicity levels, higher specificity and lower persistence in the environment.

Question 4

how are biopesticides obtained?

Answer 4

Biopesticides derived from Bacillus thuringiensis, obtained mainly from the secondary metabolism of bacteria, are effective when ingested by insects. These biopesticides generate toxins which, when released by paraspore crystals during the formation of endospores, disintegrate in the insect’s intestinal tract. The active toxin, released by the action of proteases, is integrated into the intestinal epithelium, forming channels that cause cell lysis and, therefore, the cytolytic effect in insects. It should be noted that different strains of Bacillus spp attack different types of insects.