Pest Management Flashcards
define pest
it is defined by a human perspective: how they negatively affect humans
define economic theshold
threshold where action is needed to for the damage to stop
define Economic injury level
lowest population density of a pest that will cause economic damage
how can an insect be a pest
- Disease vectors
- Economic harm to agriculture
What makes some insects a pest?
- Vectors a crop disease
- Host switching
- Introduction from outside native range
- Agriculture itself
what makes some insects a pest - host switching
native insect moves from original host to crop plant
what makes some insects a pest - introduction from outside native range
now free from natural enemies and competitors
what makes some insects a pest - agriculture itself
- pests within agriculture is much worse by large monocultures
- Anything that can thrive on crop will do so at massive scale
- Lack of diversity reduces natural enemies and competitors
what is an insecticide
apply chemicals that kill insects
problems with insecticide
- Genetic resistance
- Kills natural enemies
- Release secondary pests
- Environmental damage
problems with insecticide - genetic resistance
Large population and short generation times = high resistance potential
problems with insecticide: genetic resistance - how to avoid
- Maintain untreated field as reservoir of non-resistant insects to swamp resistant gene flow
- Use judiciously. Non-continuous selection for resistance
problems with insecticide: how to avoid genetic resistance - untreated field as reservoir
- If you treat all fields, the only insects that survive have resistance
- Allowing a non-resistant population to live, they will go to the other field and will be able to die from the pesticide
problems with insecticide: how to avoid genetic resistance - use judiciously
Only use when you absolutely have to so there not a continuous selection for resistance
problems with insecticide - Kills natural enemies
- example of a multi-trophic interactions
- Broad-spectrum insecticides also kill the predators and parasitoids of the hosts
- Thus, after short-term decline, insecticide application may help the pest
problems with insecticide - Release secondary pests
- example of multi-trophic interactions
- Minor pests may expand population in the absence of target pests
problems with insecticide - environmental damage
- Includes killing pollinators and other ‘beneficial’ insects
- Contaminating soil
- Damaging human health
what are other ways to fight pests (not using insecticide)
- Biological control
- pheromone control
- sterile insect technique
explain Biological control
Using natural enemies (parasitoids and predators of the pest)
biological control - what are the problems
- May not be able to rear or introduce enemies
- Enemies may not affect pest populations
- May backfire: enemies may attack other native insects, not the hosts
biological control - what is an example of a successful biocontrol
- Cottony-cushion scale
- it is a Hemiptera that attacks citrus
biological control: successful example - cottony-cushion scale
- Pest came from Australia
- imported beetle predator and Diptera parasitoid from Australia
biological control - what are some examples of failures
- Gypsy moth
- Hawaiian Lepidoptera
explain pheromone control
Use pheromones to:
- Disrupt mating
- Attract to mass traps
- Monitor populations
pheromone control - benefits
- Targeted; not killing natural enemies and beneficial insects
- No environmental damage of insecticides
pheromone control - problems
- Only works on chemical-based mate attraction systems
- Need to know chemistry of pheromones
- May be expensive to synthesize
pheromone control - Palm Weevil
- Bait insects into a trap
- Have a bucket filled with liquid and they bait it with pheromone
- When the insects come to mate, they instead go into the trap bucket
- After trapping, the numbers decrease (not all are dead – Just lower it below the economic threshold)
explain sterile insect technique
- Sublethal (radiate enough for sterilization but not enough to kill them) dose of irradiation to reared insects
- Males sterilized but still able to mate
- Native population swamped with sterile males
- Wild female mated with sterile males lay no eggs
- Population crashes
sterile insect technique - what assumptions are made
- All males successfully sterilized
- Mating ability of makes not compromised
- Wild females mate only once
- Wild females cannot detect sterilized males
sterile insect technique - Screwworm fly
- Cattle industry caused ecological disruption: displacement of native hosts and introduction of cattle caused insect to switch host
- Insects switched hosts (from wild animals), population explosion on domestic cattle
Modern sterile insect technique
- genetically engineer males to produce offspring that die before adulthood
- Biggest problem is social acceptance – ppl freak out with genetic engineering
what is Integrated pest management (PMI)
- Integrate multiple approaches to pest management
- Accept that pests will be there, but manage them to keep them below economically harmful levels
- More a mindset than a specific method. Generally, try to minimize chemical pesticides in order to preserve their effectiveness
- Strong emphasis on monitoring populations – only spray if outbreak is imminent
- Requires coordinated action with other famers
