L15 Pests

Question 1

What are some effects of pests?

Answer 1

Crop damage
anaemia/blood loss
vectors of disease
tissue damage, disturbance, irritation, inflammation.

Question 2

what are 6 main insect pest orders

Answer 2

Coleoptera, 
orthoptera, 
siphonoptera, 
phthiraptera, 
Diptera, 
hemiptera

Question 3

How much of food production losses do insect pests cause?

Answer 3

30-40%, mostly in the developing world

Question 4

In number of people killed per year, what are to top 6 deadliest animals?

Answer 4

Mosquito - 700,000
Human - 400,000
Snake - 50,000
Dog - 25,000
Tsetse fly/Assassin bug- 10,000

Question 5

what are 7 diseases transmitted by moquitos?

Answer 5

Dengue
Japanese encephalitis
Lymphatic filariasis
Rift valley fever
Malaria
Yellow fever
West Nile virus

Question 6

What must be understood to predict how much damage pests can do?

Answer 6

Must understand physiology and ecology of pests, and create models

Question 7

What are some drawbacks of conventional farming regarding pests?

Answer 7

1. Expensive to maintain, as very highly managed: irrigation, fertilisers, pesticides, machinery.
2. vulnerable to pests
3. low BD environments, often monocultures, with high density hosts. Creates conditions where pests can increase abundance quickly.

Question 8

What is the treadmill of infestation?

Answer 8

Increased need for food or economic benefit
Intensification of agriculture
More severe pest problems and higher losses

Question 9

7 characteristics of pests

Answer 9

1. high fecundity
2. short gen times
3. boom and bust pop dynamics
4. low host specifity
5. Exhaust the environment
6. Good colonisers
7. R selected life history

Question 10

Describe an invasive pest

Answer 10

Potato Colarado Beetle - Quickly spread when Europeans started growing potatoes in USA, moved to Europe, colonised UK where potatoes have no natural resistance.

Question 11

describe the desert locust

Answer 11

Schistocerca gregaria - desert locust. Lays 180 eggs underground, forming major pest populations.
Recognised ability to ‘phase shift’ so not just one species.
can be gregaroius or solitary
Hoppers, wingless, take 30-40 days to develop into adult. Hoppers coordinate movement ‘hopper bands’ and this is slow moving so best time to implement control.
Life cycle strongly driven by climate.

Question 12

Gregarious vs Solitary

Answer 12

Gregarious:
Yellow/pink, Diurnal flight, synchronised activity, Faster development, more, smaller eggs. Shorter femurs and longer wings
Solitary:
Brown, nocturnal, Slower flight, more preadult stages, slower development, fewer larger eggs, longer femur, shorter wings.

Question 13

What 9 steps lead from climate to change of phase and migration for desert locusts?

Answer 13

1. Favourable rainfall/humidity
2. More food and survival
3. Multiplication
4. Concentration
5. Aggregation
6. Activation (change in behaviour) - morphological, colour change
7. Increased excitability
8. Swarm fusion
9. Emigration

Question 14

Describe a pattern of locust outbreaks and reason for it.

Answer 14

Locust infestation increases from 1860-1960 then drops.
Potent neurotoxic chemical pesticide developed in 40s, v persistent and effectively reduced pest abundance in 60’s. Then realised v damaging for environment. Now increasing again.

Question 15

3 problems with neurotoxic pesticides

Answer 15

Contaminate environment
Expensive
select for resistence

Question 16

Rice yield loss due to insect pests

Answer 16

Asia 31.5%
China 15.%
Africa 14.4%

Question 17

What alternatives are there to pesticides?

Answer 17

IPM - Intergrated Pest Management

1. Prevention (new resistant cultivars, GM rice with Bt toxin)
2. Prediction (surveillance and forcasting)
3. Control, manage rather than just killing (Biological control, conserve natural enemies, limited pesticide use as a last resort, Staggered plantings - if all crops removed, also wipe out natural enemies)