Sugarcane Aphid Collected in Kentucky

Doug Johnson, Extension Entomologist, University of Kentucky

Sugarcane aphid (SCA) has been collected in two western Kentucky (KY) Counties. County Extension Agents Ben Rudy in Fulton Co. and Trent Murdock in Graves Co. have collected SCA from grain and sweet sorghum respectively. Identity was confirmed by Dr. Lee Townsend, Extension Entomologist, with the University of Kentucky (UK) in Lexington. Thus far, only the two infestations have been reported. The infestation in Fulton Co. is below treatment threshold, but the infestation in Graves Co. is much larger. Regardless of size, this does confirm that this new sorghum pest which likely migrates in from the Deep South can reach Kentucky during, if late, in the production season. Sugarcane aphid is a threat to all forms of sorghum (grain, forage, sweet) and will infest many other grasses including Johnson grass, which can act as a host for reproduction and a source of infestation.

Sugarcane Aphid Reported in Tennessee

Doug Johnson, Extension Entomologist, University of Kentucky @DrDougStinkBugs

Dr.Scott Stewart (@BugStewart) has tweeted the first discovery of sugarcane aphid (SCA) in Tennessee (07/07/15) at the AgriCenter in Memphis. The aphids were found and photographed by Drew Ellis. Numbers are low, but this does indicate that the pest is moving up the Mississippi River valley.

Several of our colleagues to the mid-south have commented on the large number of  lady beetles  & larvae that are feeding on these aphids, helping to keep the pest in check. A single insecticide application will stop all that help. Do not apply until absolutely necessary!

Kentucky producers in counties along the Mississippi River and / or counties contiguous with western Tennessee counties are most likely to see this pest.

SCA was not reported in Kentucky in 2014 but was collected in western Tennessee counties and in counties in the Missouri boot-heel. It is not a foregone conclusion that SCA will reach Kentucky, but it is an important enough pest to keep on your watch list.

Grain Sorghum producers / consultants / scouts, that are Twitter followers are encouraged to follow Dr. Scott Stewart, Univ TN, (@BugStewart) along with Dr. Gus Lorenz, Univ. AR , (@guslor77) and Dr. Angus Catchot, MS. St. Univ. (@acatchot). They will be working to manage this problem in their states before the pest gets to Kentucky; if it gets to Kentucky.

KNOWLEDGE IS MONEY!

New Aphid Pest on Grain Sorghum – Sugarcane Aphid

Doug Johnson, Extension Entomologist, University of Kentucky

Figure 1. Sugarcane aphid on
sweet sorghum; Shelby Co. TN
2014. Univ. TN.

Over the past two growing seasons a difficult new insect pest of grain sorghum has been found across the mid-south. This new pest is an aphid called the sugarcane aphid, Melanaphis sacchari. Be sure not to confuse this with the yellow sugarcane aphid, Sipha flava, which has been around the lower Mississippi river valley for several years. These are two completely different insects. Before we go any further, it is important that you understand that at present, NEITHER of these aphids have been found in Kentucky. My concern is one of preparation, as both of these aphids are found in western Tennessee and southeastern Missouri.

Shelling Corn Early? Watch That Moisture!

Doug Johnson, Extension Entomologist, University of Kentucky.

Lack of rainfall has put many corn producers in a bind, forcing them to begin harvest before the normal time. Early storage results in more days of warm, moist air before we reach the relative secure air temperatures of 50^o F or below. This early harvest is compounded because the kernels are often still at very high moisture levels. Early binning corn with 15% moisture or greater is a real gamble.

Prepare Bins for Wheat Storage.

Doug Johnson, Extension Entomologist, University of Kentucky

In just a few weeks a major portion of our 2013-14 winter wheat crop will go into storage of some type.  In fact, if this message is prompting you to prepare your bins, you are probably behind the curve. Nevertheless, there is perhaps no more important pest control strategy in successful storage of wheat than bin preparation.  Certainly there is no less dangerous and expensive alternative. The following is a suggested check list to insure you have done all you can do to prevent an insect problem in your bins.

European Corn Borer and Armyworm Active in Central Kentucky

Doug Johnson, Extension Entomologist, University of Kentucky

Fig. 1 Armyworm Damge

I have reports of scattered, mixed infestations of European corn borer (ECB) and armyworm (AW) in central Kentucky. Thus far, all infestations are in corn that does not carry insect foliar and/or stalk GMO traits (rootworm traits would not apply). This falls pretty much in line with the timing after increase (but not a dramatic increase) in moth flights in mid-to late May. I doubt that this insect pressure is large enough to be of importance to corn products carrying the appropriate insect GMO traits. Nevertheless, for those folks producing non- (insect) GMO corn, scouting is certainly in order. I have not heard any reports from western Kentucky, but west Tennessee has reported sprays for AW control on some wheat fields.

Insect Considerations for Wheat Planting Decisions

Doug Johnson, Extension Entomologist

As I travel around the countryside, I see plenty of emerging corn in fields that will likely be planted in wheat. This “Green Bridge” could lead to problems with certain insects important to wheat Production. The insect pests we need to consider have not changed from previous years, but their relative importance may have changed from last year. Fall armyworm (FAW), Hessian Fly (HF), cereal aphid complex (CAC), and wheat curl mite (WCM) are annual threats. In most years, only the CAC is of major concern. In 2012 the FAW was a considerable problem in west Kentucky, not only in wheat,but also in many forage grasses.

Stink Bugs Could Still be a Problem in Soybeans

Doug Johnson, Extension Entomologist

Because of delayed planting and a cool summer, Kentucky soybean producers are likely to have considerable acreage of late maturing soybeans. This probably causes most folks to be concerned with frost. However,this extended maturity may also set up fields for additional damage by stink bugs. Producers and consultants should remain watchful as long as pods are still filling.

Warning, Armyworms Spotted in Pastures!

Doug Johnson, Extension Entomologist, University of Kentucky

Fig. 1. Armyworm

Capture of armyworm (AW) in the IPM pheromone baited traps still remains below average. Nevertheless, this does NOT mean that there are no AWs around. While economically important populations of AW are not (yet) a wide spread problem this year, the fact remains there certainly are infested fields. The question becomes which fields are infested with an economically important population size? There is only one way to know that, and that is to scout. We do know that AW feeding on pasture grass has been reported from Butler Co. and I expect, that if one looks, infested fields will be found in other areas.

Fig. 2. Fall Armyworm

Do not confuse armyworm with fall armyworm or for that matter beet armyworm, army cutworm etc. These common names can be misleading as they sound similar but represent completely different insect species, whose ’ common features are only that they often move in large masses (hence the descriptor “Army” worm) and they feed on similar plants,generally grasses such as pastures, and large grasses such as wheat, corn, sorghum, and millet.

Most often confused in Kentucky are armyworm and fall armyworm. Armyworm also called “True armyworm” is a spring pest for Kentucky and most of the eastern U.S. It overwinters as far north as Tennessee and probably southern Kentucky, then migrates northward in the warm months. Fall armyworm (FAW) is a late summer to fall pest in Kentucky. This is due to its’ inability to tolerate cold weather, requiring it to overwinter in Texas, usually south Texas, then migrate to Kentucky and northward in the warmer months. During our current time of year armyworm is the threat to pastures, wheat and corn.

Green Cloverworms Appearing in Large Numbers in Soybeans.

Doug Johnson, Extension Entomologist

There are some unusually large populations of green cloverworms on soybeans scattered around the state. This is a very common insect in soybeans which always has the potential for economic damage, but very rarely causes economic damage. The populations I have seen thus far are not at the economic threshold, but were much larger than I am used to seeing. It makes sense to look at your soybeans, especially late planted or slow developing beans.

Green cloverworm caterpillar on soybean stem.

Green cloverworm is easy to find and easy to identify. These worms are light green with two thin white stripes along each side of the body. When fully grown, these slender worms are 1” to 1-1/2“ long. They have only three pair of prologs in the center of their body. Most of the other caterpillars in KY grown soybeans have either 4 or 2 pair of prolegs. Green cloverworm will become very active, wiggling and looping when disturbed.

These pests are foliage feeders. They will strip the leaf tissue from between the veins leaving the veins, petioles and stems behind like a skeleton.

It takes a great many of these caterpillars to cause an economic problem. Economic threshold (ET) depends not only upon the number of green cloverworms, but also on the stage of the plants, the value of the beans, and the cost of treatments. ETs may be found in:

IPM-3, KY IPM Manual for Soybeans at: http://www.uky.edu/Ag/IPM/manuals.htm and

ENT- 13, Insecticide Recommendations for Soybeans at: http://pest.ca.uky.edu/EXT/Recs/welcomerecs.html

These insects are not very hard to kill. It is most important to detect them before they reach threshold and determine if control is needed. If you find them only after the damage has been done, you can kill them, but you can’t put the foliage back on the plants!

Armyworms Active in Corn

Armyworm larvae have been reported feeding in corn. Although armyworm can damage wheat, that very rarely occurs and when it does is usually much later in the season. Certainly this entire season is much earlier than normal because of the warm January – March temperatures. Nonetheless, the general sequence of events is likely to remain the same.

Captures of armyworm moths in the UK-IPM pheromone baited traps have not been very large. Captures did begin very early this year and the first several weeks appeared to be greater than the rolling 5-year average. However, recent counts have dropped below the 5-year average. At this point I don’t expect an unusually large population for 2012. That means that one should probably concentrate their scouting efforts on those situations that are at greatest risk.