Unit 16: Integrated Pest Management and the Biological Control of Pests and Diseases

6 examples of biological control agents
Parasitic wasp, green lacewing, bt (bacillus thuringiensis), Predatory mite, nematodes, Ladybug
How do we deal with diseases without using chemicals?
Good fungi can combat bad fungi, can be put into potting soils, mycorrhizae
when chemicals secrete chemicals that inhibit root growth and seed germination of other plants
Why should I use biological pest control?
1. Less expensive
2.does not poison environment
3. insects can become resistant to pesticides
4. chemicals can be carcinogens
5. pesticides get in drinking water
6. EPA is restricting chemical use
When do you have to start regular monitoring for a pest?
when it first becomes active; taken care of before number of pests can increase
A mildly toxic chemical and can be sprayed on the plant
Spray oils
Three ways to rid of plant diseases using IPM
good sanitation to prevent fungus spores from spreading, early identification, prompt control
Nurseries utilizing IPM used __ percent fewer pesticides
Examples of natural enemies
Bacteria and fungi (diseases), insects, nematodes, spiders, birds, toads, frogs, lizards, snakes, others
How were pests prevented before the second half of the twentieth century?
Crops were grown in smaller acreage in personal farms, so natural predators could take care of the amount of pests.
Three reasons pests could not be prevented by natural predators forever
1. Natural predators needed a different environment to survive as adults. Monoculture crops destroyed the natural habitat.
2. Americans wanted a perfect product and used many chemicals.
3. Farmers killed all insects.
True or False: Some growers set aside areas for special plants for parasitic pest controls in order to encourage their development.
True or False: All biological controls need to be reapplied every year.
Example of a success story in biological control
Japanese beetle population decreased by biological controls
Two examples of infestations in the past
gypsy moth (used biological agents and traps against it) and Colorado potato beetle (resistant to many pesticides and predators such as alfalfa weevil, Mexican bean beetle, musk thistle)
Why do chemicals sometimes stop being effective?
Pests grow immune to them.
How many new immigrant species of plant pests and weeds become native to the US each year?
About 11, and 7 important ones
Why can new insects multiply rapidly?
Nature has a system of balances that helps the population of each organism stay in check. New organisms might multiply if they have no natural enemies.
How is the tomato hornworm kept under control?
Tiny wasps lay eggs on the hornworm and when they hatch, they each it from the inside out.
Two examples of pests that parasitic wasps kill
Mexican bean beetle, alfalfa weevil
How can pest controls be altered commercially to be more effective?
Disease organisms (fungi, viruses, bacteria) are grown on host insects in the lab and can be prepared as pesticides. This way, natural diseases are multiplied.
What is Bt?
bacterium that kills worms and caterpillars
How does Bt work?
It causes high gut pH in worms and caterpillars and upsets the digestive tract. The hosts eventually starved.
Pests susceptible to Bt
spruce bud worm, cabbage looper, imported cabbage worm, gypsy moth
True or False: Biological controls can kill a pest in as little as 1 or 2 days.
True or False: Biological controls generally aim to kill 100% of the pests.
False. Biological controls only kill enough pests so that it does not reduce crop production.
True or False: Biological controls are not always living things.
True. Biological controls can be viruses, bacteria, fungi, insects, or even naturally occurring chemicals that are not living.
How can chemicals aid in biological control?
repelling insects, sterilize them so eggs do not hatch, stop them from maturing into adulthood
6 ways biological controls work
1. Plant itself is resistant to disease/insect.
2. Chemicals in plant are toxic/repellent, or there are sticky hairs on the leaves and stems
3. Biological control agents produce chemicals that injure the pest.
4. They eat the pest or suck out its body fluids.
5. They grow on the pest and kill it (parasite)
6. They compete for food or space with the plant pest
VFN resistant
resistant to Verticillium wilt, Fusarium wilt, nematodes
fungi + bacteria that live in other plants without causing harm
True or False: researchers insert genes into endophytes from other bacteria so that they can combat specific insects.
2 examples of old natural insecticides
rotenone and pyrethrums
examples of promising natural pesticides
basil, big sagebrush, chilcuan, mamey, calamuse, neem tree
commercial names for neem tree
Margosan-O and BioNeem
True or False: Pests that get inside plant parts should be controlled in the adult stage.
False. They should be controlled in the first hatch stage, if possible, or else the plant will be damaged. The adult can also be made sterile so that it cannot lay eggs.
crop rotation
planting a different crop in a field year to year rather than growing the same crop on the same land for several year
life span of soil-borne diseases if plants are not present (ex. tomato wilt)
2-3 years
How many pesticides have been determined by EPA to cause tumors?
How long does it take microorganisms to break down large vats of pesticide?
48 hours
percentage of soil organisms that are beneficial
more than 99 percent
True or False: Plant diseases and insects that attack specific weeds are being developed.
bacteria and fungi
can naturally control plant pests
colonize space in soil + plant roots so that disease-producing organisms cannot survive
parasites (ex. parasitic wasps)
organisms that repel, kill, and consume another organism
plant stimulants
can cause a plant to increase its natural immunity to insects and diseases
natural enemies of all creatures in nature, search for more organisms to eat
4 steps in controlling pests
1. Nonchemical, hand-collecting of pests
2. pruning out diseased limbs
3. biological control system
4. chemicals