Newsletter

Vegetables

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

Peppers.

At the present time, all peppers that have fruit ½ inch in size or larger should be sprayed on a 7-10 day schedule for corn borer and pepper maggot control. However, in the Milford area, sprays should be applied on a 5-7 day schedule. In addition, since corn earworm catches still exceed 20 per night in the Milford area, a corn earworm spray is also needed. Since acephate (Orthene or Address) does not provide effective earworm control, Lannate or a pyrethroid should be used. In all other areas, acephate can still be used on a10-day schedule. Lannate, Spintor, or a pyrethroid should be used on a 7-day schedule. We are also starting to see an increase in aphid populations in peppers. Remember a continuous pyrethroid program should not be used to avoid aphid explosions. Trap catches can be found at http://www.udel.edu/IPM/latestblt.html or by calling the Crop Pest Hotline (1-800-345-7544- in-state only- or 1-302-831-8851).

Lima Beans.

Continue to watch for economic levels of leafhoppers that can still be found in fields throughout the state. Remember, most labeled insecticides will only provide 7-10 days of control. In fields with pin pods, you should sample for 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 or Capture can be used to control all 3 insects on lima beans.

Snap Beans.

Processing snap beans should be sprayed at the bud and pin stages with acephate for corn borer control except in the Milford area where Capture or Asana should be added to the mix for corn earworm control. A third spray with Capture or Lannate will be needed 5-7 days from harvest except in the Milford area where you will need 2 sprays between pin and harvest. Fresh market snap beans should be sprayed on a 7-day schedule as soon as pin pods are present.

Sweet Corn.

All fresh market silking sweet corn should be sprayed on a 3-day schedule except in the Milford area where sprays are needed on a 2-day schedule. Trap catches can be found at http://www.udel.edu/IPM/latestblt.html or by calling the Crop Pest Hotline (1-800-345-7544- in-state only- or 1-302-831-8851).

Vegetables - Bob Mulrooney, Extension Plant Pathologist; bobmul@udel.edu

Snap Beans and Limas.

The wet weather will favor white mold caused by Sclerotinia. If the soil has been wet for 6-10 days before bloom a fungicide is recommended. Applications should be made when 70-80% of the plants have one or more open blossoms. A second application should be made 5-6 days later. For lima beans there is a 28 day preharvest interval that must be followed if spraying with Benlate or Topsin M. Rovral can be applied up to the day of harvest and has activity against Rhizoctonia pod rot.

Snap Bean Rust.

Plant resistant varieties. Bravo and now Nova are labeled for susceptible varieties planted for the fall. Pythium damping-off control is important this time of year. Ridomil Gold in a band over the row at seeding will control this disease. Another option is Ridomil Gold PC granules in the furrow at seeding if Pythium and Rhizoctonia are present and if following another bean crop.

Tomatoes.

Early blight and Septoria leafspots are present in some plantings. Be sure to maintain sprays of Bravo and Quadris. Alternate either chlorothalonil (Bravo, Equus) or mancozeb (Dithane, Manzate) with Quadris every 7 days.

Carrots.

Maintain foliar applications of Bravo every 10 days for the control of leaf blights.

Laurel Farmer's Auction Market Report

July 21 - 27, 2000

Quantity	Produce	Price
48,150	Cantaloupes
	Athena	0.25-0.95
	Superstar	0.30-0.50
7,391	Sugar Babies
	Seeded	0.50-2.45
	Seedless	0.50-3.85
869	Honeydews	0.35-0.85
119,239	Watermelons
	Crimson Sweet
	12 up	0.40-0.90
	15 up	0.50-1.40
	20 up	0.75-2.00
	25 up	1.25-2.00
	Sangria
	15 up	0.60-1.15
	20 up	0.50-1.50
	25 up	1.25-1.80
	Mardi Gras
	20 up	1.30
	Celebration
	15 up	0.85
	20 up	0.60-2.10
	Dirmal
	20 up	0.75
	Royal Majesty
	15 up	0.80-1.00
	20 up	0.60-1.20
	Royal Sweet
	25 up	1.25
	30 up	1.70-1.75
26	Peppers
	Green	4.00-7.50
2040	Tomatoes
	Red	4.00-16.00
	Pink	3.00-10.50
	Orange	6.00-10.50
	Cherry	3.00-6.50
186	Sweet Corn Doz.	1.30-1.45
89	Cucumbers	2.00-10.00
189	Squash
	Yellow	3.00-11.00
	Green	4.00-12.00
47	Potatoes
	Red	5.00-7.00
44	String Beans	6.00-16.50
5	Eggplant	5.50
28	Pickles	4.00-6.00
	Lima Beans	14.00-27.00

Late Blight Update - Bob Mulrooney, Extension Plant Pathologist; bobmul@udel.edu

Disease Severity Value (DSV) Accumulations as of July 26, 2000 are as follows:

Remember that 18 DSV’s is the threshold to begin a spray program

Emergence Date	DSV’s July 26	Recommendation
April 27	136	5-day, mid rate
May 20	88	5-day, mid rate
May 24	88	5-day, mid rate

Accumulated 14 DSV’s since the last report.

Since many early plantings are maturing and there is no late blight present in the area, spraying is probably not justified. Later plantings that are still growing should be protected at this time. The recent wet weather will favor foliage diseases such as early blight, late blight, and Botrytis vine rot, and the tuber diseases soft rot, pink rot and leak. Leak can become a problem if the weather gets very hot. Ridomil applications back at flowering or planting are looking like a good investment given the current weather pattern. Hopefully we will get some dry weather soon so you can dig.

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

Pickling Cucumbers.

Phytophthora fruit rot is a disease that can infect all cucurbit fruit including pickling cucumbers. Fruit rot is a different phase of crown and root rot, all caused by Phytophthora capsici and other Phytophthora spp. The symptoms are initially large water soaked lesions which develop a white dense growth on the fruit. The disease can spread rapidly and fruit collapse. This continues after harvest. Like the crown and root rot phase, high soil moisture (typically standing water) for two days allows the sporangia to form and release zoospores. Secondary infections then occur. Infection can also occur in fall pickles following a spring crop which was under standing water.

Water management is critical to reducing damage from this disease. Avoid planting susceptible crops in low lying areas where standing water is common. Plant on raised beds and subsoil between crops to avoid layers that are impervious to water. A three year rotation is important. Crops to avoid in the rotation are all cucurbits (including melon, watermelon, squash and pumpkin) and pepper, tomato and eggplant.

Gummy Stem Blight.

Weather conditions are excellent for spread of gummy stem blight on watermelon. Continue to apply Quadris (11-15.4 oz./A) alternated with chlorothalonil on a 7-day interval or according to the MELCAST program for watermelons. This fungicide combination has consistently given the best results in research trials in Delaware and Maryland.

Melcast for Watermelons