Posts Tagged ‘pea aphid’

Vegetable Crop Insects – April 10, 2010

Thursday, April 29th, 2010

Joanne Whalen, Extension IPM Specialist; jwhalen@udel.edu

Asparagus
With the predicted warm temperatures, you can expect to see an increase in egg laying by asparagus beetles adults on spears. As a general guideline, a treatment is recommended if 2% of the spears are infested with eggs. Since adults also feed on the spears, a treatment is recommended if 5% of the plants are infested with adults. For a picture of asparagus beetle eggs, adults and larvae please refer to the following link: http://www.extension.umn.edu/distribution/horticulture/M1199.html

Cabbage
Continue to scout fields for imported cabbage worm and diamondback larvae. The first larvae can be found and sprays will be needed before they move deep into the heads. As a general guideline, a treatment is recommended if you find 5% of the plants infested with larvae. There are a number of effective materials available for worm control. Please refer to the following link for a list of materials http://ag.udel.edu/extension/vegprogram/pdf/colecrops.pdf

Melons
As soon as plants are set in the field, begin scouting for aphids, cucumber beetles and spider mites. When sampling for aphids, be sure to watch for beneficial insects as well, since they can help to crash aphid populations. As a general guideline, a treatment should be applied for aphids when 20% of the plants are infested, with at least 5 aphids per leaf, but before populations explode.

Peas
We are starting to see an increase in aphid populations. On small plants, you should sample for aphids by counting the number of aphids on 10 plants in 10 locations throughout a field. On larger plants, take 10 sweeps in 10 locations. As a general guideline, a treatment is recommended if you find 5-10 aphids per plant or 50 or more aphids per sweep. When sampling dry land peas, you may want to reduce the threshold, especially if they are drought stressed. Be sure to check labels for application restrictions during bloom.

Sweet Corn
Be sure to scout the first emerged fields for cutworms and flea beetles. As a general guideline, treatments should be applied for cutworms if you find 3% cut plants or 10% leaf feeding. In order to get an accurate estimate of flea beetle populations, fields should be scouted midday when beetles are active. A treatment will be needed if 5% of the plants are infested with beetles.

Vegetable Crop Insects

Thursday, April 22nd, 2010

Joanne Whalen, Extension IPM Specialist; jwhalen@udel.edu

Asparagus
Be sure to check for asparagus beetles laying eggs on asparagus spears. As a general guideline, a treatment is recommended if 2% of the spears are infested with eggs. Since adults will also feed on the spears, a treatment is recommended if 5% of the plants are infested with adults.

Cabbage
Continue scouting fields for imported cabbage worm and diamondback larvae. As a general guideline, a treatment is recommended if you find 5% of the plants infested with larvae.

Peas
Be sure to sample for pea aphids on all stages of peas. On small plants, you should sample for aphids by counting the number of aphids on 10 plants in 10 locations throughout a field. On larger plants, take 10 sweeps in 10 locations. As a general guideline, a treatment is recommended if you find 5-10 aphids per plant or 50 or more aphids per sweep. Be sure to check labels for application restrictions during bloom.

Vegetable Crop Insects

Thursday, April 8th, 2010

Joanne Whalen, Extension IPM Specialist; jwhalen@udel.edu

Seed Corn Maggots (SCM) Control in Spring Planted Vegetables
We continue to observe flies actively laying eggs in a number of situations including recently plowed fields, especially when a cover crop is plowed under or when manure was applied to a field. Spring planted vegetables susceptible to maggot damage include cole crops, melons, peas, snap beans, spinach, and sweet corn. Control options can include commercial applied seed treatments, or soil insecticides; however, not all options are available for all crops. Please refer to the labels as well as the 2010 DE Commercial Vegetable Recommendations for control options.

Cabbage
As soon as plants are set in the field, begin scouting fields for imported cabbage worm and diamondback larvae. As a general guideline, a treatment is recommended if you find 5% of the plants infested with larvae.

Peas
Be sure to sample for pea aphids as soon as small seedlings emerge. On small plants, you should sample for aphids by counting the number of aphids on 10 plants in 10 locations throughout a field. On larger plants, take 10 sweeps in 10 locations. As a general guideline, a treatment is recommended if you find 5-10 aphids per plant or 50 or more aphids per sweep. In general, aphid development is favored by cool, dry weather which slows beneficial activity but is favorable for the development of aphids. Be sure to check labels for application restrictions during bloom.

Vegetable Crop Insects

Friday, April 10th, 2009

Joanne Whalen, Extension IPM Specialist; jwhalen@udel.edu

Cabbage
Begin scouting fields for imported cabbage worm and diamondback larvae. As a general guideline, a treatment is recommended if you find 5% of the plants infested with larvae. If both insect species are present, Avaunt, Coragen the Bt insecticides, Proclaim, Rimon, Spintor, Synapse or Radiant have provided control.

Peas
Be sure to sample peas for pea aphids as soon as small seedlings emerge. On small plants, you should sample for aphids by counting the number of aphids on 10 plants in 10 locations throughout a field. On larger plants, take 10 sweeps in 10 locations. As a general guideline, a treatment is recommended if you find 5-10 aphids per plant or 50 or more aphids per sweep. The recent cooler temperatures will slow the activity of beneficial insects but favors the development of pea aphid populations.

Vegetable Crop Insects

Friday, April 11th, 2008

Joanne Whalen, Extension IPM Specialist; jwhalen@udel.edu

Seed Corn Maggots (SCM) Control in Spring Planted Vegetables
We continue to observe flies actively laying eggs in a number of situations including recently plowed fields, especially when a cover crop is plowed under or when manure was applied to a field. Spring planted vegetables susceptible to maggot damage include cole crops, melons, peas, snap beans, spinach, and sweet corn. Control options can include commercial applied seed treatments, or soil insecticides; however, not all options are available for all crops. The hopper box treatment, Latitude (imidacloprid) is available in our area and is only labeled on sweet corn. Please refer to the labels as well as the following link for control options – http://ag.udel.edu/extension/vegprogram/publications.htm.

Peas
Be sure to sample peas for pea aphids as soon as small seedlings emerge. Before the recent rains, weather conditions (cool and dry) were favorable for aphids. On small plants, you should sample for aphids by counting the number of aphids on 10 plants in 10 locations throughout a field. On larger plants, take 10 sweeps in 10 locations. As a general guideline, a treatment is recommended if you find 5-10 aphids per plant or 50 or more aphids per sweep. Be sure to check labels for application restrictions during bloom.

Scout Alfalfa for Alfalfa Weevil and Pea Aphids

Friday, March 28th, 2008

Joanne Whalen, Extension IPM Specialist; jwhalen@udel.edu

Be sure to sample alfalfa fields for small alfalfa weevil larvae feeding in the tips of plants. Early damage will appear as a round, pinhole type of feeding. Once you detect tip feeding, a full field sample should be taken. You will want to avoid treating fields too early since it may result in multiple applications. Also, be sure that you do not confuse clover leaf and alfalfa weevil larvae. Cloverleaf weevils are generally larger at this time of year and have a distinct white stripe lined with red down the middle of their backs. Although cloverleaf weevils can cause damage during cool, dry springs, controls are generally not needed for cloverleaf weevils. For pictures of cloverleaf weevil and alfalfa weevil, please refer to the following links:

http://www.ipm.iastate.edu/ipm/icm/1997/4-21-1997/icloverweevil.html
http://www.ent.iastate.edu/imagegal/coleoptera/curculionidae/0212.47alfalfalarva6in.html

You will also want to sample fields for pea aphids. Heavily infested plants may turn yellow and wilt. Pea aphids prefer cool, dry conditions and can be a problem in both the first cutting and during spring seedling establishment. This species tends to congregate on the tips of alfalfa plants where they feed on young, succulent developing shoots. To sample for aphids, clip alfalfa stems at the base of the plant and record the number present per plant. You may want to examine plants over a white bucket to collect any aphids that are dislodged from the plants. In seedling stage alfalfa, a treatment should be considered if you find 5 aphids per stem. As a general guideline, you should consider a treatment in alfalfa less than 10 inches tall if you find 40-50 aphids per stem. The treatment threshold for alfalfa 10 inches or taller in height is 75-100 per stem.