We are almost done harvesting milo for grain in Thomas County. This is the first season all of us have dealt with sugarcane aphids from beginning to end. The majority of fields in the county have been treated 4 times for aphids. This does seem like a lot of sprays; however, in these fields, yield reports are good. In these fields, SCA was spotted early and treated at or below threshold.
There was a few fields that were treated late, according to threshold. SCA reached the top of the plant before spraying. A couple of weeks later, the lower leaves completely desiccated due to aphid pressure. These yields are much lower than average. Other reports are were volume is high, 17%-19% moisture, test weight is low. Could this be from SCA?
UGA Extension Entomologist Dr. David Buntin says, yes, this can be the result of SCA. However, test weight be also be related to wet and dry cycles. And this season will certainly be marked by wet and dry cycles. Another issue we have noticed are small heads and large heads. Dr. Buntin says when heads are in two or three different stages of growth, this is result of SCA. SCA don’t have huge phytotoxic effect of feeding, but lots of feeding over time delays heads emerging.
At this stage, we still need to check heads for aphids. Mississippi saw a 20% yield reduction when aphids persisted into the heads.