Posts Tagged ‘20:6’

Lettuce and Spinach Disease Control

Thursday, April 26th, 2012

Bob Mulrooney, Extension Plant Pathologist;

We received a lettuce sample last week in the plant clinic from a high tunnel operation with lettuce drop. The following are the fungicide recommendations for the two lettuce diseases of importance in our area. These are best used preventatively. Spring lettuce season is beginning and growers should take precautions to help control Bottom rot (Rhizoctonia) and Lettuce drop (Sclerotinia) which may cause potential problems. For Bottom rot, apply Endura 70W (boscalid, FRAC code 7) at 8.0 to 11.0 oz 70W/A, or iprodione (FRAC code 2) at 1.5 to 2.0 lb 50WP/A or OLF should be applied one week after transplanting or thinning and 10 and 20 days later. For Lettuce drop, apply Endura (FRAC code 7) at 8.0 to 11.0 oz 70WG/A or iprodione (FRAC code 2) at 1.5 to 2.0 lb/A, or Quadris (azoxystrobin, 11) at 0.40 – 0.80 fl. oz/1000 row ft 2.08SC beginning one week after transplanting or thinning and again at 10 and 20 days later. For more information on control of Bottom rot and Lettuce drop and other important diseases of lettuce please see the 2012 Delaware Commercial Vegetable Production Recommendations Guide.

If white rust or downy mildew are a concern on spinach, prior to symptom development, apply the following on a 7 to 10-day schedule: Quadris (azoxystrobin, 11) at 12.0 to 15.5 fl oz 2.08SC/A, or Cabrio (pyraclostrobin, 11) at 12.0 to 16.0 oz 20EG/A, or Reason (fenimadone, 11) at 5.5 to 8.2 fl oz 500SC/A, or Tanos (famoxodone +cymoxanil, 11 + 27 ) at 8.0 to 10.0 oz 50W/A. Rotate to one of the following fungicides: Ranman (cyazofamid, 21) at 2.75 fl oz 400F/A, Revus (mandipropamid, 40) at 8.0 fl oz 2.08F, or Presidio (fluopicolide, 43) at 3.0 to 4.0 fl oz 4SC/A, or Actigard (acibenzolar-S-methyl, P) at 0.50 to 0.75 oz 50WG/A, or Aliette (fosetyl Al, 33) at 3.0 lb 80WDG/A, or fixed copper (FRAC code M1) at labeled rates (Copper containing fungicides may cause some phytotoxicity), or Ridomil Gold Copper (mefenoxam + copper, 4 + M1) at 2.5 lb 65WP/A (on 14-day schedule). For more information please see the Delaware Commercial Vegetable Production Recommendations.

White rust on upper leaf surface

White rust on lower leaf surface of spinach

Vegetable Crop Insects – April 27, 2012

Thursday, April 26th, 2012

Joanne Whalen, Extension IPM Specialist;

Asparagus beetles adults can still be found laying eggs and feeding 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.

Continue to scout fields for imported cabbage worm and diamondback larvae. 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.

Watch for aphids in the earliest transplanted fields. In past years, we have been asked about ants being found near melon transplants. In many cases, if ants are present you should look carefully on the undersides of leaves for melon aphids. Ants are commonly found associated with melon aphids in fields. They are often present in fields to collect honeydew from the aphids and can even hinder predation by other insects. As a general guideline, a treatment should be applied for aphids when 20 percent of the plants are infested, with 5 aphids per leaf.

Continue to sample fields 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. When sampling dryland peas, you may want to reduce the threshold, especially if they are drought stressed. Be sure to check labels for application restrictions during bloom.

As soon as plants emerge, be sure to sample fields for Colorado potato beetle adults, especially if an at-planting material was not used. Low levels of the first emerged adults can now be found. A treatment should not be needed for adults until you find 25 beetles per 50 plants and defoliation has reached the 10% level

Sweet Corn
Be sure to scout 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 mid-day when beetles are active. A treatment will be needed if 5% of the plants are infested with beetles.

University of Delaware Small Fruit Twilight

Thursday, April 19th, 2012

Tuesday, May 22, 2012     6:00-8:00 p.m.
Carvel Research and Education Center
16483 County Seat Highway
Georgetown, DE 19947

Participants will have the opportunity to tour experimental plots and hear about current research on June-bearing and day-neutral strawberries, blueberries and blackberries.

Strawberry research includes plasticulture variety trials with USDA selections from the Beltsville breeding program; summer planted and overwintered day neutral varieties; spring 2011 planted, overwintered, and crown thinned day neutral varieties for summer 2012 production; use of shade cloth and reflective mulch for temperature reduction in day neutral strawberries; and root inoculant and mustard seed meal treatments for root health and soil disease management in strawberries.

Blueberry research includes a 2011 planted variety trial with southern highbush selections; a mulching material study; and a planting hole treatment study.

Blackberry plots are concentrated on evaluating primocane bearing fall fruiting varieties from the University of Arkansas breeding program.

Also featured will be insect management programs and emerging insect pests of small fruits (spotted wing Drosophila).   Extension specialists and associates will be on hand to lead the tour and answer questions.

Strawberry tastings and light refreshments served.

To register, contact Karen Adams at (302) 856-2585 ext. 540 or email

For additional program information, contact Gordon Johnson,, (302)-856-2585 ext. 590,

2012 Wye REC Strawberry Twilight

Thursday, April 12th, 2012

Wednesday, May 9, 2012     6:00-8:00 p.m.
Wye Research and Education Center
Farm Operations Complex, 211 Farm Lane, Queenstown, MD
(Directional signs will be posted.)

You’ll hear University of Maryland and USDA small fruit experts discuss the current season’s challenges and the impact that the new fruit pest may have on the industry.

You’ll see: USDA Moveable High Tunnel plots with plasticulture strawberry production; University of MD Strawberry High Tunnel plots with table top production demonstration and bio-fumigation trial; and Outdoor Plasticulture Fertility Trial plots with Chandler strawberries.

Refreshments will be served.

The meeting will be held rain or shine.  Pre-registration is not necessary. For additional program information, contact Mike Newell,, (410) 827-7388. If you need special assistance to attend this program, please contact Debby Dant, (410) 827-8056, no later than May 2, 2012.