agriculture

Dr. Ed Bynum has addressed some unsubstantiated rumors flying around the High Plains; 1) that sugarcane aphid has become resistant to insecticides in Mexico and 2) that it is now able to develop on corn and is damaging corn in Mexico. I tried to address this last topic in my post last week, but Dr. Bynum has provided more detail on both issues in his newsletter post today . The bottom line is that there is no evidence of insecticide resistance and no evidence that the aphid can damage corn.

Many people on the High Plains are finding what looks like sugarcane aphids on corn and to a lesser extent cotton, and the question we are receiving is whether the aphid will get on these crops and, if so, will it become a problem. The answer to the first part is a definite YES; they will get on all of our plant species. In the past few weeks we have had billions of winged adults flying from sorghum fields and all of them need to land somewhere. They are basically like flakes of ash from a giant volcanic eruption and will settle out over the landscape. The answer to the second part of the question is that neither corn or cotton is a good host for the aphid. Small aphid colonies are being found on these crops but they are not expanding rapidly and will not get anywhere near pest status, at least if our aphids behave like sugarcane aphids do in Mexico and south Texas. Sandy Endicott from DuPont Pioneer monitors the sugarcane aphid situation in Mexico and the southern U.S. and provided so...

Headworms and Late Corn Fall Armyworm Corn earworm and fall armyworm adult trap captures are up significantly in the last week and this means headed sorghum should be scouted for headworms. It also means that late planted non-Bt corn should be scouted for fall armyworm. Corn earworm is not an economic problem in corn, but fall armyworm can do a lot of damage to ears if it infests them prior to hard dough stage. Prevathon and Belt are good choices for control of fall armyworm in corn and they will not flare spider mites (which are also being found readily in corn and sorghum). As headworm insecticides they will not flare sugarcane aphids in sorghum.  New Invasive Aphid Pest Sipha maydis, which we are choosing to call the hedgehog aphid after Colorado State University's lead, was found in Lipscomb and Hockley counties on sorghum on the same day last week. Given the distance between discoveries it is likely that the aphid is widely distributed on the High Plains and we ...

Experience with the sugarcane aphid in the last few weeks has prompted us to lower our treatment thresholds. The new thresholds can be found on our Sugarcane Aphid News website . The article concludes with suggestions for tank additives for sugarcane aphid control. 

Dr. Ed Bynum, Extension Entomologist in Amarillo, has published a good summary of the spider mite situation in sorghum this year. I have seen some fairly heavy infestations in fields but don't have time to write. And Dr. Bynum's article is better than I could do anyway. Spider Mites in Sorghum, Texas Panhandle Pest News, August 11, 2015.  

Some area sorghum fields are experiencing significant numbers of aphids, but not just sugarcane aphid the recently arrived pest from the south. We also have high numbers of yellow sugarcane aphid, greenbug and corn leaf aphid. Of these, the corn leaf aphid is the only one that is not a threat. Blayne Reed, Ed Bynum and I put out the first sugarcane aphid control experiment today just east of Hale Center. The pre-treatment count averages were something like 70 sugarcane aphids per leaf, 60 yellow sugarcane aphids and 30 greenbugs. (I have not formally tallied the numbers yet, but these are best guesses from my tired brain.) Dr. Bynum wrote an excellent article on the practical and important differences between sugarcane aphid and yellow sugarcane aphid, and it can be found here . He discusses biology, damage and thresholds. As you scout fields be sure to note the number of sugarcane aphids, yellow sugarcane aphids and greenbugs separately. As Dr. Bynum notes in his article, we don't...

It has been a very strange summer; early indications pointed to a bad fall armyworm year, but trap captures in that last two weeks suggest that we might get a break. As the graph above shows, fall armyworm trap captures at Lubbock are well below the three year average. Kendra Bilbrey, Cochran County Extension Agent, has also been operating fall armyworm traps and her data agree with the very low fall armyworm moth numbers found at Lubbock.  Kendra Bilbrey's fall armyworm trap data from Cochran County.  This is great news for sorghum because fall armyworm is part of the headworm complex. Corn earworm (cotton bollworm) is the other part. I don't have trap data for corn earworm, but my field sampling tells me that the numbers are around normal. Additionally, late planted corn that is entering green silk stage will draw corn earworm and fall armyworm away from sorghum. Green silk corn is highly attractive to these insects and neither of these pests can tell whether the corn on whi...

In the July 8th edition of FOCUS I promised to write more detailed information on sorghum midge. This year a lot of sorghum was planted earlier than normal in order to avoid the potential worst problems associated with sugarcane aphid. (Congratulations if you employed this IPM practice! It seems to be paying off now that sugarcane aphid is firmly established in Southern High Plains counties.) In general, sorghum that completes bloom before August 4th or so in our part of the Southern High Plains will escape economic midge damage. However, some of this early sorghum and the abundant Johnsongrass can serve as early hosts for midge and give later populations a head start. It is too soon to know what midge populations will be like this year, but on balance we have plenty of egg-laying hosts in the system. As I started this article I saw an excellent summary from Angus Catchot and Jeff Gore at Mississippi State University. This article is so good that I am going to link to it as most of wha...