Vegetables

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

 

Cabbage.

We can still find economic levels of DBM and cabbage looper in fall cabbage fields. The treatment threshold is 5% of the plants infested. 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, Intrepid  (8 oz/a) or Confirm (8 oz/acre) will also provide control.

 

Lima Beans.

Continue to scout fields for corn earworm. In some cases, 2 applications may be needed for earworm control. A treatment is recommended for corn earworm if you find one worm per 6 foot of row.

 

Peppers.

Continue to spray peppers on a 5-7 day schedule for beet armyworm, corn borer, corn earworm, and fall armyworm. Aphid populations have also increased, especially in fields were a continuous pyrethroid program was used. Lannate, Assail, Actara, Fulfill or Provado will provide aphid control.

 

Snap Beans.

Sprays are still needed at the bud and pin stages on processing snap beans for corn borer control. A corn earworm material will also be needed at the pin spray for corn earworm.  After the pin spray, sprays will be needed on a 5-6 day schedule 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 decision in processing snap beans  (http://www.udel.edu/IPM/traps/latestblt.html and our link to http://www.udel.edu/IPM/thresh/snapbeanecbthresh.html).  As soon as pin pods are present, fresh market beans should be sprayed on a 5 to 7-day schedule.

 

Spinach.

The first webworms have been found in recently emerged spinach. Be sure to watch for both webworms and beet armyworms and apply controls when worms are small and before they have moved deep into the hearts of the plants. Also, remember that both insects can produce webbing on the plants. Confirm, Intrepid or Spintor will be needed for beet armyworm control. If webworms are the predominant species,  Ambush, Pounce, Confirm (6-8 oz/acre), Intrepid (8-10 oz) or Spintor (4-8 oz/acre) should be used. Generally, at least 2 applications are needed to achieve control of webworms and beet armyworm.

 

Sweet Corn.

Fresh market silking sweet corn should be sprayed on a 2-3 day schedule throughout the state. Be sure to check our website for the most recent trap catches and information on how to use this information to make a treatment decision in fresh market sweet corn (http://www.udel.edu/IPM/traps/latestblt.html and http://www.udel.edu/IPM/thresh/silkspraythresh.html ) .

 

 

UD IPM Black Light and Pheromone Trap Counts

Average Number of Moths per Night: September 5 to September 9, 2003

 

* Numbers can change quickly. For the most recent trap counts, access the website at (http://www.udel.edu/IPM/traps/latestblt.html) or call 1-800-345-7544 (in-state); 1-302-831-8851 (out-of-state). Counts are updated on Tuesday and Friday.

 

 

 

Vegetable Crop Diseases – Bob Mulrooney Extension Plant Pathologist; bobmul@udel.edu

 

Lima Beans.

Lima bean pod rot, caused by Phytophthora capsici, was diagnosed this week affecting a large area. The fungus had infected pods high in the canopy, which was also observed in 2001. It will infect pods on the ground, initially, then spreads in the canopy after last weeks favorable weather.

 

Sweet Corn.

Late sweet corn is being infected with several problems as mentioned last week. Common rust, Southern corn leaf blight continue to be the most common diseases identified. One field was diagnosed with root rot causing some stunting and yield reductions. Fusarium and Phoma were two fungi identified with that root rot.

 

 

 

Field Crops

 

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

 

Soybeans.

Corn earworm populations continue to be low in fields throughout the state. The cooler weather has resulted in a decrease in corn earworm moth catches; however, double-crop beans are still attractive to egg laying moths. Fields with flat pods or seeds just beginning to enlarge are at the most risk. Ames Herbert from VA indicated last week in his newsletter that "these fields should be scouted until moths stop flying, or pods become mature. Most of the full season crop is at or near the point where fields are no longer attractive to moths.  Basically, once seeds are full sized and pods toughen up, they are no longer at risk. "  A combination of rainy weather, cool evenings and warm days, can result in populations crashing from disease organisms, so be sure to watch for diseased worms before making a treatment decision. In addition, as we move into September corn earworm will begin to enter their diapausing (overwintering) stage so do not treat too quickly. The treatment threshold for podworms is 3 per 25 sweeps in narrow fields and 5 per 25 sweeps in wide row fields (20-inches are greater). The following materials will provide corn earworm control in soybeans: Ambush, Baythroid, Asana, Mustang MAX, Pounce, Warrior (all pyrethroids) Steward, or Larvin.

 

Small Grains.

Although we have not seen widespread Hessian fly problems for a few years, a number of research plots in the region as well as some fields in Virginia did experience significant lodging this past spring. In most cases, this was the result of spring infestations. Plants attacked in the spring have shortened and weakened stems that may eventually break just above the first or second node, causing plants to lodge near harvest. Since the fly survives as puparia ("flax seeds") in wheat stubble through the summer, you should still consider this pest as you make plans to plant small grains.  In some cases, infested fields were planted after the fly free date. This traditional method of control is based on delaying planting until after flies have emerged.  Warm fall weather conditions can extend fly emergence and egg laying beyond the fly-free dates, but these dates should still be used as a guideline for planting. Since we rarely see plants stunted in the fall, we still feel that most of the damage we see is occurring from spring infestations. Plants attacked in the fall at the one-leaf stage may be killed outright. Wheat attacked later in the fall will be severely stunted, with the first tillers killed and plant growth delayed. Plants infested in the fall can easily be recognized by their darker than normal bluish coloration and leaves with unusually broad blades. A combination of strategies should be used to reduce problems from Hessian fly:

(1)   Be sure to completely plow under infested wheat stubble to prevent flies from emerging;

(2)    Avoid planting wheat into last season's wheat stubble, especially if it was infested with Hessian fly;

(3)    Avoid planting wheat next to last season's wheat fields - the most serious infestations can occur when wheat is early planted into wheat stubble or into fields next to wheat stubble;

(4)   Eliminate volunteer wheat before planting to prevent early egg laying;

(5)   Do not use wheat as a fall cover crop near fields with infestations;

(6)   When possible, plant after the fly free date (Oct 3 – New Castle County; Oct 8 – Kent County; Oct 10 – Sussex County) ;   and 

(7)   Plant resistant varieties – You should look for varieties that have resistance to Biotype L.  Although some of these varieties may not be appropriate for Delaware, the following is a list of varieties from North Carolina that have exhibited good resistance to Biotype-L : P 26R12, P 26R38, P 26R61, Roane, USG 3350, and USG 3430. 

 

As far as chemical control, most of the recent data with seed treatments and foliar insecticides has come from North Carolina where populations have been heavier and fall infestations more widespread in recent years. These chemical strategies are designed to control infestations at planting and will not last to control spring infestations. Earlier work in Maryland did not show an economic benefit from using seed treatments for Hessian fly management since most of our infestations occur in the spring.

 

 

 

Field Crop Diseases – Bob Mulrooney Extension Plant Pathologist; bobmul@udel.edu

 

Field Corn.

Gray leafspot, anthracnose and common rust are increasing since last week on late planted corn. If corn is dented, there is no economical benefit from applying any fungicides at this time. Be sure to check fields for stalk rots by pinching stalks close to the ground. If stalks crush easily between your thumb and forefinger, schedule that field for early harvest to prevent losing it to a wind storm.

 

 

 

Grain Marketing Highlights - Carl German, Extension Crops Marketing Specialist; clgerman@udel.edu

 

September Soybean Production Estimate Shocks Grain Trade.

USDA now estimates U.S. soybean production at 2.643 billion bushels, 219 million bushels less than the August production forecast. The soybean production forecast was 114 million bushels less than the average pre-report trade guestimate of 2.757 billion bushels. Ending stocks for U.S. soybeans are now placed at 135 million bushels, 85 million bushels less than the month ago estimate. The soybean market is currently trading anywhere from 16 to 20 cents per bushel higher as the lower production and ending stock numbers are being bid into prices.

 

World ending stocks for soybeans are now forecast at 34.77 million metric tons, 4.21 MMT less than the August estimate and slightly less than last year. The reduction is believed to stem largely from the reduction in the U.S. production estimate.

 

U.S. Corn.

U.S. corn production, estimated at 9.944 billion bushels, was above the pre-report average trade forecast of 9.8 billion bushels and 120 million bushels less than USDA's August estimate. Ending stocks for U.S. corn now placed at 1.064 billion bushels, above the average pre-report estimate of 990 million bushels, are also 120 million bushels less than the August forecast. Although the corn production estimate was initially viewed as disappointing by commodity speculators, it is likely to see some spillover effect from the soybean trading pit.

 

World corn ending stocks forecast at 74.30 MMT, are well below the August estimate of 78.76 MMT and last year's carry in of 98.10 MMT. World coarse grain ending stocks, now forecast at 106.41 MMT, is well below the August

estimate of 111.74 MMT and last year's carry in of 142.06 MMT.    

 

Market Strategy.

Short crops have long tails, meaning that prices typically peak just prior to, during, or shortly after harvest. Just when prices peak depends upon what happens to the production forecast from the September estimate to the actual harvest. If the production forecast declines further then commodity prices will peak later. It wouldn't be surprising to see commodity traders taking into account the reduction in this week's crop condition report for both corn and soybeans, if not by the end of this week then sometime next week. The reason being that the realization will set in that this week's decline was not reflected in the September crop report.  The current jump in soybean prices should be used to bring new crop soybean sales to the 50% level of expected production.