We had a great meeting last week with UGA Extension Grain Entomologist Dr. David Buntin. He came to address insect issues in corn and also update us on sugarcane aphids. I worked with many growers on the aphid last season, and our information was very helpful to Dr. Buntin as well. 2015 was our first full year with the aphid. Here are some notes I put together from his meeting which includes some varieties that show resistance/tolerance to SCA:
The varieties below were researched by UGA Extension Entomologist Dr. David Buntin and researchers from LSU or Texas for tolerance/resistance to sugarcane aphids. Remember, no variety is completely resistant to sugarcane aphids. For us in South Georgia, planting with a seed treatment is still advised. Grain sorghum should also be scouted for sugarcane aphids within two weeks of emergence.
The good news is sugarcane aphids do not overwinter in Georgia. But we have to look for them within 2 weeks of planting, especially if we don’t have a seed treatment. All the females are born pregnant, and they have a very high reproduction rate. They are also not known to transmit any viruses.
Varieties reported as having tolerance/resistance to SCA
Georgia State Variety Trial (Dr. David Buntin, UGA)
Dr. David Buntin: Upon evaluation of all grain, silage and forage sorghum entries in the GA state variety trial for SCA resistance/tolerance, DKS 3707 was the most resistance. However, none of the entries were highly resistant. There was very little resistance/tolerance in the silage and forage types.
United States Sorghum Board Results (Researcher at LSU or in Texas)
Insecticide Summary for SCA
- Threshold: Treat when 50 or more aphids are found on 25 percent of the crop.
- Sivanto 200SL @ 4 – 10 oz, (21 d PHI); 2ee for 4-7oz.
- Transform @ 1.0 – 1.5 oz, (14 d PHI); IF Section 18 approved for 2016.
- Chlorpyrifos @2 pt (60 day PHI), ? Efficacy, 7-10 days.
- Dimethoate, Lannate, malathion & chlorpyrifos @ 1pt are not effective.
- Pyrethroids are not effective, because they flare aphids.
- Add neonicotinoid seed treatment if available.
- Start with Sivanto, follow with Transform (if available) to rotate chemistries.
- Transform for harvest infestations (14 d PHI).
- 2015 research showed adjuvants have little benefit.
- Ground: 10+ GPA
- Aerial: 5 GPA
No chemigation for Sivanto or Transform.
No labeled insecticides for sweet sorghum!