Sugarcane Aphids in Grain Sorghum

Threshold levels have been reached are will be soon on late planted grain sorghum (milo).  Every field of grain sorghum that I have looked at in the past several weeks has had some level of infestation from these fairly new pests.

This aphid pest that once only infested sugarcane has quickly become a pest of grain sorghum throughout the Southeast.  Since it is still a relatively new pest we are still learning about pest thresholds and the best tools to control it.  

Planting early and seed treatments can help early infestations, however much of our sorghum is planted later in the season and is untreated seed.  Fields should be scouted early and often to monitor pest levels and to be able to track the increase in populations across the field.

Threshold levels developed in the Delta range from 25% infested leaves with colonies of 50+ or 30% infested plants with colonies of 100+.  Either way once we get near this threshold we need to apply a suitable insecticide to reduce populations and protect yields.

Products that we have available are Transform, Sivanto, Chlorpyrifos (Lorsban, and others), and Dimethoate (Cygon,).  Dimethoate has had variable results and is not one that we would recommend. Chlorpyrifos has done well but the high rate requires a 60 day pre-harvest interval.  Sivanto has couple of labels for sorghum and was effective at the 4 oz. rate in trials.  the pre-harvest interval is 21 days.  Transform is another product that has label specifically for this pest.  it has a 14 day pre-harvest interval and has been effective even at low rates (0.75 oz) providing good coverage is accomplished.

Coverage is the key and can be improved by using at least 15 gallons per acre, by increasing pressure, and with the addition of a non-ionic surfactant at 0.25% v/v.

Disease Forecasting for Producers

There are some good tools that are easy to access and use for producers as well as county agents and crop consultants.  Several of the diseases that we see on crops in the southeast overwinter in warmer climates and migrate with weather pattern and crop maturity from south to north.

We have sites that track the movement of diseases such as southern corn rust, soybean rust and downy mildew of cucurbits.  You can also see what is going on with legumes, pecans, and onions. You can go to:  http://www.ipmpipe.org/  to find all of these services. Once there you will see maps that shows where diseases have been confirmed and areas that are being scouted.

This is for the current southern rust situation.  There are similar maps for soybeans and cucurbits.

Georgia Clean Day

Gwinnett County is a long drive but it may be worth it you have alot of unwanted or old pesticides

Georgia Clean Day                                                                                                                           

This is an excellent opportunity to dispose of pesticides that you have been holding because you had neither an economical nor legal means to dispose of them. Canceled and suspended pesticides by definition cannot be used and must be disposed of, often as hazardous waste. Some reasons to participate in this program are: 1. No disposal fees for those who participate in the 2015 program. 2. The disposal contractor secures all permits and approvals. 3. Disposal contractor takes possession of the waste and thereby becomes the generator. 4. Participants are not directly involved with state and federal regulatory agencies. 5. All materials eligible for destructive incineration will be destroyed. 6. Minimization of ongoing liabilities from continued storage of these wastes on your property.

The Georgia Department of Agriculture is proud to announce it has secured limited funding for a one day Georgia Clean . The event will be held at the Gwinnett County Fairgrounds 2405 Sugarloaf Parkway

Lawrenceville, GA 30045 from 8:00am – 3:00pm on July 22, 2015.

Southern Rust Found in South Georgia

Andy Shirley, Mitchell County Ag Agent, confirmed southern rust in a growers field late last week. Check out Dr. Dewey Lee's blog post to learn more.

http://georgiagraincrops.com/corn/southern-rust-found-in-georgia-corn-dang-it

Peanut Pegging Zone Sampling

Peanuts produce their own nitrogen and are great at scavenging for phosphorous and potassium.  The one nutrient that is critical, especially on larger seeded peanuts like Georgia 06G, is calcium.  Since most of our peanuts were planted by the first of May now is the time to determine if you need to apply calcium.  We can easily determine calcium levels by taking a pegging zone soil sample. 

To take a pegging zone sample simply take a soil sample in the zone where the peanuts will eventually be pegging.  This sample needs to be taken to a depth of 3".  Calcium levels in this sample will help us determine if there is a need for additional calcium and if so how much.  We can supply the needed calcium by applying gypsum or landplaster.  Lack of calcium especially in Georgia 06G will result in decreased yields due to excessive pops or empty pods.