BI207-- types of pest control

why control matters

• insects threaten our health, livelihoods and food security

• prevention and control is costly and may have consequences for health of humans and environment

• decisions for producers, governents and consumers

history of pest control

prehistoric- handpicking, beating, burning

biological control- using natural enemies

resistant crops- use of inherited genetic resistance— artificial selction

chemical control- sukohur, arsenic, plant extracts; synthetic revolution mid 20th century

types of pest control

• cultural (crop rotation)

• mechanical/ physical (weeding)

• biologicalcontrol (lady birds

• resistant cops (GM)

• chemical control (pesticides)

cultural control

• often preventable

• selection of varieties

• crop rotation

• tillage or burning of stubble

• pest free rootstock/ seeds

• nutrient management

• sowing date

• crop spacing/ seeding rate— more plants incase too many get eaten by insects

• trap crops— more attarctive to the bothering pests rather than the food or crop really being grown

• intercropping— reduce monoculture

mechanical/ physical control

• fly swatter

• picking pests

• mesh screens in greenhouses

• crop fleeces, netting— helpful for carrots and cabbage

• storing of products at certain temps, humidity

pheromones and other insect attractants

• insect signalling

• can be used to mis direct behaviour and/ or preventing reproduction

• monitoring— detecting isnects

• pheromone mass trapping— lured and killed

• mating disruption— pheromones prevent mating

• specific

biological pest control

• “biocontrol”

• natural enemies/biocontrol agents

• classical biocontrol (pests of invasives)

• augmentation

• conservation

• microbial control

genetic manipulation of pests

e.g. sterile male technique

• Screwworms - Cochliomyia hominivorax

• attack healthy animal tissue

• sterile insect technique (SIT)

host plant resistance

• breeding

• genetic engineering

  • physical barreirs

  • resource aquisition, growth and vigor

  • defensive chemistry and signalling

chemical pest control

• insecticides (chemical poisons)

  • developed during and after 2nd world war

  • initially effective and cheap

  • replaced traditional forms of chemical, cultural and biological

  • insecticide “boom”— as a result developed resistance over time

• pesticides (chemical poisons)

  • penetrate cuticle, inhalation into tracheal system, oral ingestion

  • different modes of action (nerve poisons, development, metabolic processes)

  • most broad spectrum

  • different formulations

benefit of pesticides

• infrastructure

• health

• ecosystems

• yields have gone up

• killing mosquities, ticks, bedbugs etc.

how are pesticides applied

• sprays— manual/ aerial

• controlled droplet application

• seed, dust, granule

chemical insecticides

• most widely used

• mode of action: most chemicals act on insect nervous system and cause rapid death

• types: botanicals, synthetic insecticides, insect growth regulators

chemical pest control

insect growth regulators (IGRs)

• affect growth via interference with metabolism or development

• e.g. juvenile hormone mimics or chitin synthesis inhibitors

success of chemical pesticides

• rapidly effective

• wide variety available

• array of uses and application routes

• little biological expertise needed

• cost effective

types of insecticides

• organochlorines e.g. DDT

• cyclodines

• organophosphates

• carbamates

• synthetic pyrethroids

• synthetic neonicotinoids

• can maybe cause cancer

increase in pesticide use— but not effective?

• despite increase duse, damage by insect pests increased dramatically

• E.g. prop. crops damaged by pests doubled 7-13% from 1950-1985 in US

• potentially due to

  • insecticide resistance— resistance to one can mean resistance to many, or different mechanisms of defence against one pesticide

  • pest resurgence— pests reproduce quicker than its predator— increased number after pesticide usage

  • secondary pest outbreak