Posts Tagged ‘nematodes’

Vegetable Disease Updates – September 17, 2010

Friday, September 17th, 2010

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

Nematodes in Veggies
Fall is the best time to soil sample for nematode pests such as root knot, lesion, and other plant parasitic nematodes. After fall harvest but before any fall tillage is done, take soil cores six inches deep between plants in the row. Samples should be taken in the root zone of the old crop. Twenty cores/ sample should be taken from random spots in the field and placed in a plastic bucket, gently mixed, and a pint of soil submitted for analysis. Large fields should be subdivided into blocks of 15- 20 acres each and sampled separately. Nematode test bags and instructions are available for purchase from the county Extension offices. Samples cost $10.00. Fall sampling for root knot nematodes is strongly recommended for fields that will be planted in cucumbers, watermelons, cantaloupes, lima beans or other high value vegetables where root knot could reduce production. Forms and instructions are also available on the web at http://ag.udel.edu/extension/pdc/index.htm. Just a reminder, as I mentioned last week, do not take nematode samples until we get some rainfall if the soil is very dry.

Fall sanitation
In vegetable production it is not a good idea to leave old crop residue in the field any longer than necessary. If the crop is allowed to survive after harvest, fungi that cause many diseases continue to increase on the surviving plants. This allows higher numbers of the fungi to potentially survive until next season. Sanitation (plowing or disking the old crop) will help prevent pathogen carry-over.

Lima Beans
To date, I have not heard about or seen any samples of downy mildew in lima beans. The weather has not been favorable for infection.

Fall Nematode Sampling

Friday, September 10th, 2010

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

The fall is generally the best time to sample for nematode populations in vegetables and field crops. After harvest is complete but before any fall tillage is the best time for taking survey samples. With the very dry conditions, however, I would delay taking fall nematode samples until we get some rain. Samples taken from very dry soil may not be representative of what is present in the field.

One other observation is that nematode soil samples should not represent any more than 20 acres. Nematodes are not uniformly distributed in the soil and it would be easy to miss significant numbers if a single sample of 20 soil cores represented a large acreage. I am not trying to generate more work, just better information on which to make an informed recommendation.

Mocap EC 24c Label for Limas and Snap Beans Withdrawn

Thursday, May 20th, 2010

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

Mocap EC section 24c special local need label for lima and snapbeans in DE was withdrawn by Bayer Crop Science after EPA determined that human health risk findings required reduced application rates. The recommended reduced rate can offer control on garden symphylans, but can only provide suppression to nematodes. Since root knot and other nematodes will not be controlled the label was withdrawn. This does not affect the use of Mocap 10G, if growers have granular applicator boxes for their planters this formulation is effective at the label rates.

Agronomic Crop Diseases

Thursday, April 8th, 2010

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

Wheat
Wheat development is later than normal due to the adverse wet weather conditions beginning back in the fall. It is not too early to remind growers, consultants and fieldmen about several resources that are available for monitoring Fusarium head blight (scab). Two websites are available, the first is the scab predictor site http://www.wheatscab.psu.edu/ with the risk map tool and the second is a new site called Scab Smart.

Scab Smart Web Site Can Help With Head Scab Management
The U.S. Wheat and Barley Scab Initiative (UWBSI) has a Web site that provides farmers with information on how to manage Fusarium head blight, commonly known as scab.

Scab Smart is designed to serve as a quick guide to the integrated strategies that result in optimum reduction of scab and its primary associated mycotoxin, deoxynivalenol (DON).

On the site, producers can access information by management strategy or wheat class. Scab Smart’s content will be updated on an ongoing basis as new management information becomes available.

The site can be accessed through this website http://www.scabsmart.org

Stripe Rust and Leaf Rust
On another topic, stripe rust and to a lesser extent leaf rust, are increasing in the South. There have been reports of greater than normal infection levels of stripe rust in Louisiana, Texas and Oklahoma. It is never easy to predict if it will make it to Delmarva. Stripe rust has not been a problem in Delaware since 2006 and 2007. When it has occurred it has had variable effects on wheat depending how mature the crop is when the disease appears. Most of the damage in the past has occurred in the northern parts of the state. When scouting wheat later in the season keep this disease in mind. Alerts will be given if it gets closer to us. Generally applications with a triazole containing fungicide made at flag leaf emergence through heading will provide good control.


Stripe rust on wheat.

Corn
There have been growers with increasing southern root knot nematode populations in field and sweet corn, especially when pickling cucumbers, soybeans, and lima beans have been in a rotation. The best way to reduce root knot nematodes in corn is with an at-planting application of Counter 15G. The data I have seen for seed treatments that might be effective for root knot have not been consistent at this time. They are definitely worth looking at but how effective they will be is still a question in my mind.

End of the Season Vegetable Disease Notes

Friday, September 18th, 2009

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

Nematodes in Veggies
Fall is the best time to soil sample for nematode pests such as root knot, lesion, and other plant parasitic nematodes. After fall harvest but before any fall tillage is done, take soil cores six inches deep between plants in the row. Samples should be taken in the root zone of the old crop. Twenty cores per sample should be taken from random spots in the field and placed in a plastic bucket, gently mixed, and a pint of soil submitted for analysis. Large fields should be subdivided into blocks of 15-20 acres each and sampled separately. Nematode test bags and instructions are available for purchase from the county Extension offices. Samples cost $10.00. Fall sampling for root knot nematodes is strongly recommended for fields that will be planted in cucumbers, watermelons, cantaloupes, lima beans or other high-value vegetables where root knot could reduce production. Forms and instructions are also available on the web at http://ag.udel.edu/extension/pdc/index.htm.

Fall Sanitation
In vegetable production it is not a good idea to leave old crop residue in the field any longer than necessary. If the crop is allowed to survive after harvest, fungi that cause many diseases continue to increase on the surviving plants. This allows higher numbers of the fungus to potentially survive until next season. Sanitation (plowing or disking the old crop) will help prevent pathogen carry-over.

Mocap EC Receives a 24c Label for Nematode Control on Snap and Lima Beans in Maryland

Friday, June 26th, 2009

Kate Everts, Vegetable Pathologist, University of Delaware and University of Maryland; keverts@umd.edu

Notice! Mocap EC received a 24c Label for nematode control on snap and lima beans in Maryland today (Friday, June 26, 2009). For more information about Mocap see the article in Weekly Crop Update 17:13.

Mocap EC Receives a 24c Label for Nematode Control on Snap and Lima Beans in Delaware

Friday, June 12th, 2009

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

Mocap EC received a 24c label for use in Delaware on snap beans and lima beans to control nematodes. Mocap 15G has been labeled for use on snaps and limas for a long time to control nematodes particularly root knot nematode (Meloidogyne incognita). Since nobody has insecticide boxes on their planters anymore if you needed to control root knot, especially in lima beans, nothing else is labeled except for fumigants. This 24c label will allow use of Mocap EC for either applying in a band over the row and incorporated or shanked into the soil two inches from the seed at planting. It is very important to keep Mocap from coming into direct contact with the seed since it can reduce germination. This is also a toxic product and all personal protection equipment (PPE) needs to be worn. Be sure to read the label for all the important information: http://www.rec.udel.edu/Update09/MocapEC24cDE.pdf. The Delaware Dept of Agriculture granted this label in a timely manner for use this season after receiving the request from Bayer CropScience, the manufacturer of Mocap insecticide/nematicide.

Nematodes in Vegetables

Friday, September 19th, 2008

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

Fall is the best time to soil sample for nematode pests such as root knot, lesion, and other plant parasitic nematodes. After fall harvest, but before any fall tillage is done take soil cores six inches deep between plants in the row. Samples should be taken in the root zone of the old crop. Twenty cores/sample should be taken from random spots in the field and placed in a plastic bucket, gently mixed, and a pint of soil submitted for analysis. Large fields should be subdivided into blocks of 15- 20 acres each and sampled separately. Nematode test bags and instructions are available for purchase from the county Extension offices. Samples cost $10.00. Fall sampling for root knot nematodes is strongly recommended for fields that will be planted in cucumbers, watermelons, cantaloupes, lima beans or other high value vegetables where root knot could reduce production. Forms and instructions are also available on the web at http://ag.udel.edu/extension/pdc/index.htm