Orchardgrass leaf streak disease

I was out looking at an orchardgrass field yesterday that was infected with the disease "leaf streak", also called brown stripe. This is becoming more of a problem in the mid-Atlantic. Agronomists across the region have been noticing vigor and persistence problems with orchardgrass. Orchardgrass stands which would typically last for 6-8 years are lasting for 3 years or less. Regrowth has been slow, pests and diseases are damaging stands, and stands have been performing poorly for unexplained reasons. I know this is not news to many of our growers. To try to determine what is happening the Mid-Atlantic Orchardgrass task force was established in 2008. Unfortunately, we don't have many control options for forage diseases. It is recommended to maintain proper fertility, suppress weeds, and two rotate to a non-grass crop for two years prior to establishing orchardgrass. The orchardgrass task force has begun conducting variety evaluations for disease and control studies. Hopefully we will have more answers in the future to address the problems in orchardgrass. For more information and disease pictures visit the the overview of the Mid-Atlantic Orchardgrass Task Force. 

Bill Bamka

Spider mites in soybeans

Starting to see some soybean fields with spider mites. Given the current hot, dry weather it would be a good idea to scout fields for spider mites. Scouting information and treatment thresholds can be found in the Mid Atlantic Pest Management Guide for Field Crops 

Bill Bamka

Potassium Deficiency in Soybeans

I have been out looking at some soybean fields and have started to see some potassium deficiency in some fields. Every year I see some fields with potassium deficiency in our sandy soils in the south. It is not uncommon to see in double crop beans where the straw is baled. Potassium deficiency is seen as yellowing or browning and sometimes necrosis along the edges of older leaves. As the deficiency becomes more severe the symptoms move higher up the plant. Below is a picture of potasium deficiency in soybean. Potassium deficiency should not be confused with manganese deficiency. With manganese deficiency the veins of the leaves remain green.

Bill Bamka

Leaf Hoppers

We are starting to see continued increases in leaf hopper populations in alfalfa fields. Also while scouting soybean fields I was also finding leaf hoppers. Keep an eye on alfalfa fields as the nymphs can cause damage pretty quickly. Once you start to see yellowing or "burn", yield has already been reduced. The threshold for 4-6 inch tall alfalfa is 50 leaf hoppers per 100 sweeps. Soybeans in the seedling stage are most susceptible to injury. If you see plant damage and average 8 leaf hopper per sweep, control may be necessary.

Bill Bamka

European Corn Borer

I was called to look at some field corn in Burlington County because of insect damage. The damage was due to some significant populations of european corn borer larvae. This is not suprising given that the RCE Vegetable IPM program was reporting very high populations of adult moths in black light traps earlier this spring. Those of us in field crops tend to forget about ECB because of Bt hybrids. Remember though we can still treat for ECB in the required non-Bt refuges and non-Bt planted fields. Rescue treatments are not that effective when the larvae are deep in the whorl or in the stalk. Information on scouting and treatments for ECB can be found in the Mid-Atlantic Pest Management Recommendations for Field Crops. Keep in mind that ECB can also attack sweet corn and peppers.

Bill Bamka