Pests and Pest Control

1. Pests and Pest Control Tamboli A.Z. Department of Zoology S.M.Joshi College, Hadapsar. F.Y .B.Sc.

2. Pest Control Is An Everlasting Problem • How does an organism become labeled as a pest species? • Pest control: winning the battles but losing the war. • Designing better mouse traps.

3. A Pest Defined • Technically, any organism (bacteria, fungi, plant, animal) that has a negative effect on human health or economics (food). • Realistically, any organism we don’t want around (factors in convenience and esthetics).

4. Integrated Pest Management(IPM) • An approach to controlling pest populations using all suitable methods - chemical and ecological. • The goal is to brings about long-term management of pest populations that also have minimal environmental impact

5. Pesticides (Biocides) • Insecticides (dah!) • Herbicides (not just the weedy plants) • Rodenticides (mammalicides) • Fungicides (mildews and rusts) • Acaricides (ticks and mites) • Bacteriocide (e.g. antibiotic)

6. Pesticide “Improvements” (?) • Second-generation pesticides • Organic chemical (organochlorines). • Used after WWII (presently in developing countries) • Synthesis begins with petroleum (“oil”) • Mechanism of actions often unknown. • Bioaccumulation & Biomagnification. • Toxic to animals (humans) and agricultural plants. • Pests developed resistance.

7. Chemical pesticides lose effectiveness Resistant pest populations produce next generations Resistance to Pesticides

8. Some Examples of Insect Food Chains

9. Human Health Effects • Acute: high dose, short-term response, rapid onset (headache, nausea, vomiting, respiratory failure, death). Agricultural workers suffer acute poisoning during pesticide application. • Cronic: low-dose, long-term exposure, outcome takes many years before noticed (cancer, dermatitis, neurological disorder, birth defects, sterility, endocrine system disruption, immune system depression). Neighborhoods downwind of agricultural use; farm families; the innocent.

10. Environmental Effects • Bioconcentration: • Movement against a concentration gradient; typically fat soluble. • Biomagnification: • Movement through the food chain to higher trophic levels; typically persistant. • Bioaccumulation: • Combined effect of both; chemicals are typically fat soluble and persistant.

11. The DDT Case Study • 1938; dichloro-diphenyltrichloroethane (DDT) • Extremely toxic to insects, but seemed nontoxic to humans and other mammals. • Cheap. • Broad-spectrum and persistent • Effective for disease prevention (typhus fever, malaria) • Expanded agricultural production • Paul Muller awarded Nobel prize in 1948

12. Natural Pest Control • Cultural control • Control by natural enemies • Genetic control • Natural chemical control

13. Insect Life Cycle

14. Cultural ControlGet rid of the alternative host!

15. Control by Natural Enemies

16. Genetic Control • Plants or animals are bred to be resistant to the attack of pests. • Chemical barriers. • Physical barriers. • Introduction of genes into crops from other species: transgenic crops (Bt) • Sterile males are released into pest population.

17. Natural Chemical Control • Manipulation of pests’ hormones or pheromones to disrupt the life cycle. • Japanese beetle trap.