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USCP Agronomy Check
BRENT BEAN
LUBBOCK, TEXAS
Over the past two years, there has been quite a bit of negative buzz in the agricultural media and rural coffee shops about sugarcane aphid (SCA), Melanaphis sacchari, in sorghum. With so much talk, I thought I’d take a moment to discuss the reality versus the perception of the incursion of SCA into North America.
Record yields, despite SCA
Of the 8.5 million acres of grain sorghum planted in the U.S. in 2015, the best estimate is that only about one-third of these acres reached SCA infestation levels that warranted an insecticide application.
In South Texas and Louisiana, the two regions that have the most experience with SCA, losses attributed to the insect were much less in 2015 compared to 2014, largely because of better management practices. It is expected that acres will either increase or remain the same in 2016 in these two regions.
Based on the tone of much of the popular press, most folks would get the impression that grain sorghum yields were devastated in 2015. In reality, grain sorghum production was up at an all-time high of 76 bushels an acre with an estimated production of 597 million bushels. Of the 8.5 million acres of grain sorghum planted, 93 percent was harvested, again an all-time high.
Although SCA is a new pest in sorghum in the U.S., it has been present in other countries for years. In Africa, which grows more grain sorghum than anywhere in the world, SCA in sorghum has been present for many years and is simply managed like any other pest.
U.S. entomologists expect SCA to follow the path of other aphids that when first appeared in U.S. crops were a major issue, but soon became pests that could be managed successfully and economically. Good examples of this are the greenbug aphid in sorghum and the Russian wheat aphid in wheat. Both were major problems initially, but quickly became pests that could be easily managed.
Management tips
Management of SCA will be greatly helped by nature. When a new pest becomes present in a crop or region there is a time lag that takes place as its natural enemies build up. As was famously said in the movie Jurassic Park, “nature finds a way.”
But there are proactive measures farmers can take to manage SCA. These are:
• Scout fields early and often. Once SCA infest a field they can reach an economic threshold level in just a few days.
• Once threshold level is reached, insecticide application should be made immediately. Delay can result in high yield loss. Good spray coverage is also essential in controlling SCA.
• Plant early. In many areas of the country, early planting will allow sorghum to avoid the sugarcane aphid altogether, and if nothing else, may result in the need for only a single insecticide application rather than multiple applications.
• Avoid the use of pyrethroid insecticides whenever possible. These insecticides greatly lower the population of beneficial insects which are critical in keeping SCA populations in check.
• Seed treatments have been shown to be very effective in controlling early season infestation of SCA.
Excellent resources on SCA management have been put together by USCP in collaboration with many university entomologists. These resources can be accessed on the USCP website at sorghumcheckoff.com . ∆
BRENT BEAN: Agronomist, United Sorghum Checkoff Program
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