Sugar Cane Aphids and Grain Sorghum

Sugar Cane Aphids and Grain Sorghum

The middle of January may seem a funny time to be talking about a pest that needs warm (hot) weather to proliferate and do its damage and a crop that won’t be planted for another 3 to 4 months. But as has been pointed out to me, many of you maybe booking your seed through this time period. You may be questioning how many acres worth to buy and if you should buy a “resistant or tolerant” variety.

The Sugar Cane Aphid infestation of the summer of 2015 was intense, awful, (choose your own word), a true “bug run”, but just because it happened in 2015 does not necessarily mean it will repeat itself in 2016. The “perfect storm” of conditions for 2015 included the right weather (hot/humid), the right predominant wind direction to bring the aphid in, lack of natural predators at the time, unprecedented acres of a host plant, etc. It could repeat itself, but in 35 years I’ve only seen what I would call a true “bug run” about 3 times…………one of them was last summer.

Plan for the worst, hope for the best. With that train of thought these would be my recommendations for the 2016 sorghum crop.

  1. Fertilize for my yield goal. A well-nourished, well planted crop is able to withstand more stress than a malnourished one. Don’t treat your grain sorghum crop like an afterthought.
  2. Buy insecticide treated seed or treat it yourself. This will give the crop early (30 days?) protection and let it get a good start. (May be particularly important on late planted sorghum).
  3. Plant Sugar Cane Aphid tolerant hybrids. Yes, I would buy that “resistant or tolerant” variety. The breeders have well adapted good yielding varieties for our area. (More on this later.)
  4. Eliminate as much as possible host plants (Johnson grass) around the grain sorghum field (ditches, waterways, etc.).
  5. Scout (or have it scouted) your field for aphids.
  6. Spray insecticides at perhaps a lower threshold of aphids than many did in 2015 with a higher residual chemical early and the lower residual when closer to harvest. In other words spray earlier at a decent (higher) rate for longer residual.

This may be important! The term “resistant” or “tolerant” varieties, usually does NOT mean you will not get Sugar Cane aphids on the plant. They probably will. It means that variety will be more tolerant of having an infestation giving you more time to address the situation. In some instances these varieties may be able to withstand the aphid population if it is not severe. It may mean they can produce more grain with an infestation than other varieties, but it usually does not mean you will not have aphids. They are a good tool in the toolbox, but NOT a cure all.

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