CULTURAL PEST CONTROL

Question 1

Site Selection

Answer 1

Selecting a site that is pest free or similarly choosing a crop species that is particularly well suited for a site can circumvent various pest problems.

Studying the field history and sampling soils can aid in making this decision.

Question 2

Sanitation (Habitat Modification)

Answer 2

Pest problems occur when conditions essential for survival (food, shelter, alternate host) are met by the environment. An important management tool is one that eliminates pests by removing their spaces of refuge, breeding grounds, and overwintering sites.

For instance cleaning al plant debris from a previous crop can significantly limit future infestation. Thoroughly clean tools, use certified seed, steam clean soil, install screens for greenhouses, eliminate weedy borders.
For instance draining areas where there is standing water can eliminate mosquito breeding grounds.

Question 3

Destruction of Alternate Hosts

Answer 3

Can effectively suppress certain pest populations.
Example: Control of curly top virus in sugar beets involves the destruction of weeds that are alternate hosts for the carrier ‘beet leafhopper’.

Question 4

Smother Crops

Cover Crops

Answer 4

Are grown for their ability to suppress weeds and cash value. They are effectively employed in crop rotations and planted in high densities to rapidly occupy a site.
Includes: cereals, sorghum, safflower, field corn, and domestic sunflowers.

Are used for the same reason except generally not harvested. Instead are used because of their ability to shelter beneficials, suppress weeds, provide soil nutrients, prevent erosion, increase organic matter,
reduce pesticide runoff, etc.

Commonly used in vineyards and orchards between rows.
Be careful as in some cases cover crops may invite pests or may outcompete the crop if not managed properly.
Popular cultivars include: strawberry clover, annual clover, cereal grasses, annual grasses, vetches, or combinations.

Question 5

Intercropping

Answer 5

Growing more than one crop in a field at the same time: multiple crops are planted in alternating strips or intersown into a main crop. By doing so empty spaces are taken up to outcompete weeds.
Trap rows of alfalfa can be planted in between cotton rows to lure lygus bugs away from the cotton and toward the alfalfa where these insects present little damage.

Question 6

Crop Rotation

Answer 6

The intentional planting of specific crop sequences to improve crop health. One of the oldest cultural practices it provides effective control for certain host-specific plant pathogens, nematodes, and insects by disrupting the pests life cycle. Tends to work well against soil borne pests.
Target: Pests that cannot survive for more than 1-2 years without the host crop and without a suitable alternate host range.
Weeds are sometimes controlled with a combination of rotation and herbicide applications.

Question 7

Planting and Harvest Dates

Answer 7

Should be chosen to favor crop development and discourage pests.
For weed management, choose a planting time that favors germination of the crop over weed species.
In California potatoes and winter-grown carrots can be planted when potato cyst nematode is not active.
Early harvest of potatoes, in Northern California, can effectively reduce the incidence of tuber blemishes caused from nematodes.

Question 8

Irrigation and Water Management

Answer 8

Excess soil water excludes oxygen to the plant roots and is a primary factor in root/crown diseases, such as rot. Excess drainage can also favor numerous hard to control weeds such as nutsedge and barnyard grass.

Underwatering can lead to plant stressors that can allow susceptibility to pathogens or other pests.

Irrigation systems should be considered carefully as many techniques have pro’s and con’s associated depending on crop and technique including: flood irrigation, sprinkler, and drip.

Finding out the water hold capacity, and retention rate of a soil (building a water budget accordingly) can help avoid pest problems associated with over/underwatering. Such steps can be takes through the use of information provided from CIMIS weather stations online, through local newspapers, or on the radio.

Question 9

Fertilizer and Soil Amendments

Answer 9

The of the following can influence the activity of many pest species to the advantage or detriment of the host plant.

Excess nitrogen can be a contributing factor in the incidence of brown batch in nectarines, as well as the peach twig borer.