Be on the look out for Palmer Amaranth

I received a phone call from Mark Van Gessel, the Extension Weed Specialist from the University of Delaware (who also serves as our RCE Field Crops Weed Specialist). He was letting me know that they have found several fields in Delaware with Palmer Amaranth in them, and that we should be on the look out for it in New Jersey. At this point we do not have any Palmer Amaranth present in New Jersey that we are aware of.  According to Mark, "It looks a lot like our “typical” pigweeds, but it has no hairs on the stem, often a white watermark on the leaves, long petioles, and long slender seedheads." The concern is that this species is very aggressive, and is referred to as "pigweed on steriods".  It has the ability to be resistant to many different herbicides. It is proving to be a headache to cotton producers across the south. The populations found in Delaware are not herbicide resistant at this point. Dr. Van Gessel notes it is important that we identify it early and aggressively start to manage it before it becomes a problem. The University of Georgia has a fact sheet on the biology of Palmer Amaranth . Kansas State University has a guide to help in identification of Palmer Amaranth .

Bill Bamka

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