AGRI 412 ACTIVITY QUIZ 2

Which BEST explains why food webs are more stable than food chains?

• Food webs show only herbivores and carnivores.

• Food webs connect multiple organisms, allowing alternative feeding pathways.

• Food chains always involve decomposers.

• Food chains do not include abiotic components.

A farmer notices that cabbage aphids become more destructive after harvest season when crops are already declining. Which factor explains this phenomenon?

• Habitat advantage

• Starvation

• Decline of food supply

• Functional response

Which pest is most likely to spread fungal plant diseases in a humid rice field?

• Termites

• Mosquitoes

• Nematodes

• Aphids

A release program fails because the control agent cannot find the host — which factor (below) is the MOST likely cause?

• The pest’s protective retreats (e.g., galls, tunnels) reduce exposure to the agent.

• The agent is highly host-specific.

• The pest has a high reproductive rate.

• The pest is native to the area.

Which strategy would likely reduce the need for frequent augmentative releases?

• Stop planting nectar sources to discourage pests.

• Improve habitat for resident natural enemies (flower strips, reduced broad-spectrum insecticides).

• Increase use of broad-spectrum insecticides.

• Import more exotic predators each season.

A farmer wants to control a caterpillar outbreak. Which biological control agent is MOST suitable?

• Bacillus thuringiensis (Bt)

• Lady beetles

• Lacewings

• Predatory mites

Which insect virus is MOST likely to be transmitted by a parasitoid wasp rather than through insect feeding?

• Nuclear Polyhedrosis Virus (Npv)

• Entomopox Virus

• Ascovirus

• Iridovirus

If Serratia spreads too widely in the field, what potential ecological risk might occur?

• Beneficial insects may also be infected

• It will increase soil fertility

• It will promote fungal resistance

• It will eliminate viral infections

If a farmer applies Beauveria bassiana excessively, which unintended effect may occur?

• Faster decomposition of organic matter

• The fungus starts attacking crops

• Soil fertility decreases

• Reduced effectiveness due to fungal resistance in pests

What is the ecological advantage of using microsporidia in pest management?

• They kill insects immediately upon infection

• They spread mainly through parasitoid vectors

• They persist long-term in pest populations, weakening them

• They can also infect vertebrates