On Wednesday, Stephanie Holliefield in Brooks County confirmed sugarcane aphids in grain sorghum. I got calls from two growers in Thomas County today reporting SCA also. In both fields reported, no honeydew is present. Last season, we observed that once honeydew was present on the top of leaves, populations spread fast. Here is a picture of an adult and immatures under a leaf in a field today.
Threshold
At pre-boot, we really don’t treat until 50-100 aphids are found in 20% of the field. Last season, we found ourselves pulling the trigger later than we should have. Each situation will be different. It can be difficult to asses. We need to remember that if aphids are present in one corner of the field, they may be present in another corner, and in another spot.
Treatment
Here is updated information on our Section 18 in GA from UGA Entomologist Dr. David Buntin:
We have 2 products available, Sivanto Prime and Transform. Things we should know about application and use of these products include;
- Sivanto Prime – can be applied at 4-7 oz/acre. The 4 oz rate will do a good job and last for at least 21 days. Sivanto Prime last a little longer than Transform. This product is full labeled on sorghum with a supplemental label for the 4-7 oz rates.
- Transform WG – has been approved again by a Section 18 for Georgia, at the 0.75 to 1.5 oz rate/acre. However, one big change from last year is Transform CANNOT be used during flowering. Also, we need to remember that there are only 2 applications per season. Dr. David Buntin, UGA Entomologist recommends at least the 1 oz rate and the 1.5 oz rate is even more effective and will provide approximately 14 days of control.
Both of these products can be used on grain, silage, forage type sorghums, and sorghum/sudangrasses. But please remember that these products can not be used on sweet sorghum.