Vegetables

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

Cabbage.

Be sure to sample fall planted fields for diamondback and cabbage looper larvae. We can find both insects in recently planted fields. If both species are present, Avaunt (3.5 oz/acre), a Bt, Proclaim (3 oz/acre), or Spintor (4-5 oz per acre) will provide control. If cabbage looper is the predominant species, a pyrethroid or Confirm (8 oz/acre) will also provide control.

Lima Beans.

Be sure to sample fields carefully for corn earworm, lygus and stinkbugs. A treatment should be applied if you find one corn earworm per 6 foot of row or 15 tarnished plant bugs and/or stinkbugs per 50 sweeps. Lannate, Mustang or Capture can be used to control all 3 insects on lima beans.

Peppers.

At the present time, all peppers should be sprayed on a 7-day schedule for corn borer, corn earworm, beet armyworm and pepper maggot control. Remember, Orthene or Address will not provide satisfactory earworm control. A pyrethroid or Lannate will be needed for earworm control. Dimethoate should still be added to the mix for pepper maggot control if a pyrethroid or Lannate are used. If beet armyworms are present, Avaunt, Spintor, Confirm or Lannate will provide the best beet armyworm control. Depending on the pest complex present, a combination of products will be needed.

Snap Beans.

Processing snap beans in all areas of the state should be treated at the bud and pin stages for corn borer control. Orthene or Address should be used at the bud and/or pin stages for corn borer control. In all areas, a pyrethroid should be combined with Orthene at the pin spray for earworm control. After the pin stage, Lannate, Capture or Mustang should be used. Sprays will be needed on a 6-7-day schedule from the pin spray until harvest. Since this can change quickly, be sure to check our website for the most recent trap catches and information on how to use this information to make a treatment decisions in processing snap beans (http://www.udel.edu/IPM/traps/latestblt.html and http://www.udel.edu/IPM/thresh/snapbeanecbthresh.html). You should treat fresh market snap beans for corn borers on a 7-day schedule from the pin stage until harvest. Lannate, Capture or Mustang should be used.

Sweet Corn.

Fresh market silking sweet corn should be sprayed on a 2-3-day schedule in the Bridgeville, Concord, Dover, Harrington, Laurel and Seaford areas. In all other areas, sprays are needed on a 3-day schedule. Since this can change quickly, be sure to check our website for the most recent trap catches and information on how to use this information to make a treatment decisions in fresh market sweet corn

(http://www.udel.edu/IPM/traps/latestblt.html and http://www.udel.edu/IPM/thresh/silkspraythresh.html ). Economic levels of fall armyworm can be found in most late-planted sweet corn. Insecticides must be directed into the whorls with at least 25-30 gallons of water per acre to achieve control. In addition, at least 2 applications may be needed. Lannate, Avaunt or Warrior have provided effective fall armyworm control in whorl stage corn.

Maintain Fungicide Sprays on Watermelons -Ed Kee, Extension Vegetable Crops Specialist; kee@udel.edu

Several growers have asked about discontinuing fungicide sprays on watermelons in light of the dry weather. If growers expect to keep harvesting, fungicide coverage needs to be continued. You are protecting new tissue resulting from leaf and fruit growth. Fungicides do breakdown and new coverage is necessary. Additionally, heavy dews can provide enough moisture to support the disease causing organism. Sprays need to protect until the last harvest is finished.

Vegetable Diseases - Kate Everts, Extension Vegetable Pathologist, University of Delaware and University of Maryland; everts@udel.edu

MELCAST for Watermelons.

From the University of Maryland and University of Delaware

Latest EFI values from local weather stations

Any questions please call (410) 742-8788

EFI Values (Environmental Favorability Index)

Do not use MELCAST if there is a disease outbreak in your field, it is a preventative program.

Location 08/07/02 08/06/02 08/05/02 08/04/02 08/03/02 08/02/02 08/01/02 07/31/02

Bridgeville, DE 0 3 3 3 1 3 1

Charles Co. 0 6 0 8 0 5 0

Collins Farms 0 3 2 4 2 1 1

Galestown, MD 0 3 3 4 2 2 1

Georgetown, DE 0 0 3 3 2 3 3 3

Glenville, MD 0 0 0 6 0 1 0

Hebron 0 3 3 4 2 3 1

Hog Creek Rd. 0 3 0 3 0 1 0

Salisbury, MD 0 3 3 4 2 1 4

Vincent Farms 0 3 2 4 5 3 1

Westminster 0 5 0 8 2 0 0

White Marsh 0 6 0 3 0 0 0

The first fungicide spray should be applied when the watermelon vines meet within the row. Additional sprays

should be applied using MELCAST. Accumulate EFI (environmental favorability index) values beginning the

day after your first fungicide spray. Apply a fungicide spray when 30 EFI values have accumulated by the

weather station nearest your fields. Add 2 points for every overhead irrigation. After a fungicide spray, reset

your counter to 0 and start over. If a spray has not been applied in 14 days, apply a fungicide and reset the