Posts Tagged ‘18:9’

Transplant Shock

Thursday, May 13th, 2010

Gordon Johnson, Extension Fruit & Vegetable Specialist; gcjohn@udel.edu

The first seven days in May in 2010 saw temperatures in the high 80s and even some night temperatures in the low 70s in Delaware, and while windy, it was not excessively so. Then came the weekend of the 8th and 9th where average wind speeds doubled or tripled followed by low temperatures the middle of this week with scattered frost at night. These weather conditions illustrate the perils of setting out warm-season transplants in the beginning of May and to the need to take actions to avoid transplant shock.

Transplant shock will be evident by severe wilting, drying of leaves and stems, and, in severe cases, full plant collapse and death. This should not be confused with diseases such as Pythium damping off or damage from seed corn maggot or other soil insects.

Many of our transplants come from southern producers this time of year and there is always the potential for transplant shock when they are removed from southern greenhouses with little or no hardening and then are shipped up to Delaware in unheated trucks, especially when temperatures drop in the 40s or below during transport. Locally grown transplants are also susceptible to transplant shock if taken directly from greenhouses to the field without a hardening off process. Even with good hardening off, 40 mph winds can quickly desiccate plants if set in the field, especially without adequate windbreaks.

As a reminder, warm season vegetable transplants vary in their ability to withstand sub-optimal conditions depending on how well they have been hardened off and their inherent ability to withstand stress. Tomatoes, cucumbers, and squash are better able to handle early season stresses than cantaloupes, watermelons, or peppers.

Soil temperatures are a key factor in the establishment of warm season crops. It is important to lay plastic well ahead of planting and to have adequate soil moisture to absorb and then retain heat. When soil temperatures are too cold, root growth is minimal in these crops and root function is impaired. Water uptake is limited by low root activity and new growth and rooting-in is slowed. Root zone insects and diseases can further stress transplants and reduce stands in cold conditions.

To avoid transplant shock, make sure transplants have well developed root systems. Transplants should easily pull from trays and have full root balls. This is critical to avoid transplant shock. Do not rush transplants with poorly developed roots into the field. Make sure transplants have been hardened off well by exposing them to outside conditions, eliminating fertilizer, and controlling watering well ahead of planting. Leggy plants will be a problem in stressful conditions and should not be used if at all possible. Leggy plants are more susceptible to damage in transplanting and wind damage after planting thus subjecting them to additional stress.

It is important to plant so that soil covers the root ball and that the root ball is not exposed to drying. However, for crops such as watermelons and cantaloupes, make sure that soil does not surround the stem. Deep planting in cold wet soils will result in additional stress on melons. Extra care should be taken during transplanting during stressful periods to reduce injury to plants, particularly to root balls. Damage to roots will reduce establishment success especially in melons, cucumbers, and squash. Train planting crews so that they do minimal damage to transplants. If plants are not pulling well from trays and do not have intact root balls, plants will not survive adverse weather.

Avoid planting if weather conditions are unfavorable. Look at extended forecasts and plant on a warming trend where winds are not excessive. If heavy winds or very cold nights are expected, it is best to wait until more favorable weather returns. Often there is no earliness gained by planting in the stressful period; or gains are negated by stand losses and the need to replant areas. If weather conditions are unfavorable, you may also consider using row covers to protect plants.

Windbreaks are critical for early plantings. Use windbreaks between every bed for the early plantings and have windbreaks between multiple beds for later plantings. This year, many of our windbreaks offer minimal protection due to poor fall and winter growing conditions. Where windbreaks are not adequate, delay planting until favorable weather is in the forecast.

Vegetable Crop Insects – May 14, 2010

Thursday, May 13th, 2010

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

Leafminers in Vegetable Crops
There have been reports of leaf miners attacking spring planted vegetable crops. There are a number of potential species that attack vegetables including the vegetable leafminer, serpentine leaf miner, spinach leafminer and beet leafminer. Leaf miners can be difficult to control and we have limited experience with control strategies in our area. The following links provide information on some of the potentially important species:
http://entnemdept.ufl.edu/creatures/veg/leaf/vegetable_leafminer.htm

http://entnemdept.ufl.edu/creatures/veg/leaf/a_serpentine_leafminer.htm

http://www.umassvegetable.org/soil_crop_pest_mgt/insect_mgt/beet_leafminer.html

Cabbage
Continue to scout for diamondback and imported cabbageworm larvae. Economic levels of diamondback larvae can be found. A treatment should be applied when 5% of the plants are infested and before larvae move to the hearts of the plants.

Melons
Continue to scout all melons for aphids, cucumber beetles, and spider mites. Economic levels of aphids can be found and although beneficials (lady beetles and parasitized aphids) can also be found they are not keeping up with the aphid populations due to the recent cooler temperatures. As a general guideline, a treatment should be applied for aphids when 20 percent of the plants are infested, with 5 aphids per leaf and before significant leaf curling occurs.

Peppers
As soon as plants are set in the field, begin sampling for thrips and corn borers. On young plants, corn borer larvae can bore into the stems and petioles. In areas where peppers are isolated or corn is growing slowly, moths are often attracted to young pepper plants. Therefore, you should watch for corn borer moths laying eggs in all fields. As a general guideline, treatment may be needed if there is no corn in the area or you are using rye strips as windbreaks. You should also look for egg masses. At this time of year, thrips can damage peppers by vectoring tomato spotted wilt virus and by causing direct plant damage. Although there are no available thresholds, a treatment may be needed if you see populations increasing.

Potatoes
Continue to sample for Colorado potato beetle adults and egg laying. A treatment should be considered for adults when you find 25 beetles per 50 plants and defoliation has reached the 10% level. Once larvae are detected, the threshold is 4 small larvae per plant or 1.5 large larvae per plant. Corn borer moths are being found in BLTs throughout the state; however, flights are still low. A corn borer spray may be needed 3-5 days after an increase in trap catches or when we reach 700-degree days (base 50). If you are scouting for infested terminals, the first treatment should be applied when 10% (fresh market) or 20-25% (processing) of the terminals are infested with small larvae.

Snap Beans
All seedling stage fields should be scouted for leafhopper and thrips activity. The thrips threshold is 5-6 per leaflet and the leafhopper threshold is 5 per sweep. If both insects are present, the threshold for each should be reduced by 1/3. Be sure to also watch for bean leaf beetle feeding. Damage appears as circular holes in leaves and we have seen significant damage in recent years on the earliest planted fields. As a general guideline, a treatment should be considered if you defoliation exceeds 20% prebloom.

Sweet Corn
Continue to sample for cutworms and flea beetles. As a general guideline, treatments should be applied 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. Be sure to also watch for corn borer and corn earworm larvae in the whorls of the earliest planted fields. Although trap catches are still low, we are finding both in traps. A treatment should be applied if 15% of the plants are infested.

2010 Strawberry Twilight Meeting

Thursday, May 6th, 2010

Wednesday, May 19, 2010     6:00 – 8:00 p.m.
Wye Research and Education Center
211 Farm Lane
Queenstown, MD

Please join us for an evening in the strawberry field.

● Hear University and USDA fruit specialists discuss strawberry production systems.

● Interact with specialists to discuss concerns you may have in your strawberry operation.

● Hear the details of a new MDA specialty crop grant that will begin this summer at WREC producing out-of-season blueberry, bramble, and strawberries.

What you will see:

● Strawberry production in High Tunnels (4 varieties and several USDA advanced selections)

● Plant-based bio-fumigation trial used in the annual plasticulture system

● Early and late planted Chandlers managed in the Fall with and without floating row covers

Desserts will be available following the meeting.

No pre-registration required, however, if you need special assistance in order to attend the program, please call Debby Dant 410-827-8056 X115, no later than May 12, 2010.

***IMPORTANT NOTE***

THIS YEAR’S TWILIGHT WILL BE HELD IN THE STRAWBERRY FIELD (RATHER THAN IN THE FARM SHOP). PLEASE FOLLOW POSTED SIGNS, WHICH WILL DIRECT YOU TO THE PROPER FIELD AND PARKING AREA.

For program information, contact: Michael Newell, mnewell@umd.edu or (410) 827-7388

Equal opportunity employer and equal access programs.

Soybean Cyst Nematode Workshop

Thursday, May 6th, 2010

Tuesday, August 3, 2010  8:30 a.m.- 1:30 p.m.
Delmarva Poultry Industry Building
(former UD office building)
16684 County Seat Hwy.
Georgetown, DE 19947

Soybean cyst nematode (SCN) is a widespread and serious pest of soybeans on Delmarva. First discovered in the fall of 1979 it has been causing increased problems for growers in recent years. This workshop will cover some basics about the biology of SCN and it management and the results of the recent Delaware Soybean Board sponsored survey of SCN in Delaware. The workshop will also include visiting a small research plot to see SCN first hand and discuss symptoms, diagnosing SCN from root samples with a hand lens, and proper soil testing procedures. The workshop is suggested for agricultural professionals on Delmarva who advise soybean growers and growers who want to know more about this important pest.

Pesticide recertification credits and CCA credits in pest management will be offered for attendees.

The cost of the program is $10 per person with lunch included. The registration deadline is Friday, July 23. A registration form is available here: http://www.rec.udel.edu/Extension/Agriculture/SCN.pdf

Looking for an Enterprising Vegetable Grower

Thursday, May 6th, 2010

We have the land!  Do you have the passion?

We have created one of the most exciting new communities ever to be built in New Castle County just north of Middletown, Delaware on 1,600 acres.  There are 3,000 homes planned on our land and approximately 2,000 homes planned on neighboring lands.  We would like to incorporate locally grown produce as an integral part of our new community—The Village of Bayberry.  We have the land, an ag well, and the perfect location for an entrepreneurial farmer who loves growing and selling fresh produce.  A new farm stand building with plenty of parking will be built by us and would be included in the lease.  There is presently no competition in the area and the land is available immediately.

If interested, please call Jeff Seemans, RLA, at 302-254-0100, X214, or email him at JSEEMANS@BLENHEIMHOMES.COM.  Lease terms are negotiable as is amount of land.

Agronomic Crops Twilight Tailgate Session

Thursday, May 6th, 2010

Wednesday, May 26, 2010     6:00-8:00 p.m.
UD Cooperative Extension Research and Demonstration Area
(3/4 mile east of Armstrong Corner, on Marl Pit Rd. – Road 429, Middletown)

Join your fellow producers and the UD Extension team for an overview of University of Delaware’s Demonstration Plots at the Marl Pit Road Demonstration Site. We’ll cover highlights on grain marketing, nutrient management and pest management, as well.

We will apply for DE Pesticide and Nutrient Management re-certification credits and Certified Crop Advisor credits.

This meeting is free and everyone interested in attending is welcome.

Bring a tailgate or a lawn chair.

To register, request more information or require special needs assistance for this meeting, please call our office in advance at (302) 831-2506. Please call to register by May 25.

See you there!
Anna Stoops, New Castle County Extension
Agricultural Extension Agent

It is the policy of the Delaware Cooperative Extension System that no person shall be subjected to discrimination on the grounds of race, color, sex, disability, age or national origin.