Pest Management

Question 1

define pest

Answer 1

it is defined by a human perspective: how they negatively affect humans

Question 2

define economic theshold

Answer 2

threshold where action is needed to for the damage to stop

Question 3

define Economic injury level

Answer 3

lowest population density of a pest that will cause economic damage

Question 4

how can an insect be a pest

Answer 4

• Disease vectors
• Economic harm to agriculture

Question 5

What makes some insects a pest?

Answer 5

• Vectors a crop disease
• Host switching
• Introduction from outside native range
• Agriculture itself

Question 6

what makes some insects a pest - host switching

Answer 6

native insect moves from original host to crop plant

Question 7

what makes some insects a pest - introduction from outside native range

Answer 7

now free from natural enemies and competitors

Question 8

what makes some insects a pest - agriculture itself

Answer 8

• 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

Question 9

what is an insecticide

Answer 9

apply chemicals that kill insects

Question 10

problems with insecticide

Answer 10

• Genetic resistance
• Kills natural enemies
• Release secondary pests
• Environmental damage

Question 11

problems with insecticide - genetic resistance

Answer 11

Large population and short generation times = high resistance potential

Question 12

problems with insecticide: genetic resistance - how to avoid

Answer 12

• Maintain untreated field as reservoir of non-resistant insects to swamp resistant gene flow
• Use judiciously. Non-continuous selection for resistance

Question 13

problems with insecticide: how to avoid genetic resistance - untreated field as reservoir

Answer 13

• 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

Question 14

problems with insecticide: how to avoid genetic resistance - use judiciously

Answer 14

Only use when you absolutely have to so there not a continuous selection for resistance

Question 15

problems with insecticide - Kills natural enemies

Answer 15

• 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

Question 16

problems with insecticide - Release secondary pests

Answer 16

• example of multi-trophic interactions
• Minor pests may expand population in the absence of target pests

Question 17

problems with insecticide - environmental damage

Answer 17

• Includes killing pollinators and other ‘beneficial’ insects
• Contaminating soil
• Damaging human health

Question 18

what are other ways to fight pests (not using insecticide)

Answer 18

• Biological control
• pheromone control
• sterile insect technique

Question 19

explain Biological control

Answer 19

Using natural enemies (parasitoids and predators of the pest)

Question 20

biological control - what are the problems

Answer 20

• 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

Question 21

biological control - what is an example of a successful biocontrol

Answer 21

• Cottony-cushion scale
• it is a Hemiptera that attacks citrus

Question 22

biological control: successful example - cottony-cushion scale

Answer 22

• Pest came from Australia
• imported beetle predator and Diptera parasitoid from Australia

Question 23

biological control - what are some examples of failures

Answer 23

• Gypsy moth
• Hawaiian Lepidoptera

Question 24

explain pheromone control

Answer 24

Use pheromones to:
- Disrupt mating
- Attract to mass traps
- Monitor populations

Question 25

pheromone control - benefits

Answer 25

- Targeted; not killing natural enemies and beneficial insects - No environmental damage of insecticides

Question 26

pheromone control - problems

Answer 26

- Only works on chemical-based mate attraction systems - Need to know chemistry of pheromones - May be expensive to synthesize

Question 27

pheromone control - Palm Weevil

Answer 27

- 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)

Question 28

explain sterile insect technique

Answer 28

- 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

Question 29

sterile insect technique - what assumptions are made

Answer 29

- All males successfully sterilized - Mating ability of makes not compromised - Wild females mate only once - Wild females cannot detect sterilized males

Question 30

sterile insect technique - Screwworm fly

Answer 30

- 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

Question 31

Modern sterile insect technique

Answer 31

- genetically engineer males to produce offspring that die before adulthood - Biggest problem is social acceptance – ppl freak out with genetic engineering

Question 32

what is Integrated pest management (PMI)

Answer 32

- 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