agriculture

We all respect fall armyworm as a significant threat to High Plains corn, sorghum and cotton, and that is why we run pheromone traps to assess the potential threat during the growing season. Last year we sent some of our moths to Ashley Tessnow, a graduate student working with Dr. Greg Sword in the Dept. of Entomology at College Station. She is looking at the population genetics of fall armyworm. She sent some of her preliminary results this week, and they were a surprise; based on just 2017 moths, we seem to have a baseline level of around 30% "rice" strain. There are two strains of fall armyworm, and the rice strain feeds on rice, Bermudagrass and Johnsongrass (but can feed on corn). The "corn" strain feeds on corn, sorghum and cotton. In another surprise, the baseline level of about 70% corn strain jumped to 93% in the late June sample when we had a sudden influx of high numbers of moths for just a few days.  I sent Ashley a draft of this text, and she wisely add...

Entomologists with Texas A&M AgriLife Extension Service have released a new statewide guide on managing insect pests of cotton. The highlights of new guide include 1) description of economic arthropod pests of cotton in Texas, including their associated damage to crop growth stages, 2) description of the various sampling methods for these pests, 3) information on Bt traits available in market and their relative efficacy, and 4) description of action thresholds and management tools for each pest. Here is a link to access online version of the guide. https://lubbock.tamu.edu/files/2018/01/Cotton-Insect-Management-Guide.pdf It can also be downloaded from the Texas A&M AgriLife Extension bookstore at no cost. http://www.agrilifebookstore.org/Managing-Cotton-Insects-in-Texas-p/ento-075.htm

Suhas Vyavhare, Extension Cotton Entomologist, Texas A&M AgriLife Extension Service The EPA has approved the Section 18 Emergency Exemption for use of Transform WG in Texas to control plant bugs in cotton. This exemption is effective March 1, 2018 and expires October 31, 2018. Pests and application rates: Plant bugs (1.5 � 2.25 oz Transform WG per acre) Spray drift management: Applications are prohibited above wind speeds of 10 mph Restrictions: -    Pre-harvest Interval: Do not apply within 14 days of harvest. -    A restricted entry interval (REI) of 24 hours applies to all applications. -    Minimum Treatment Interval: Do not make applications less than 5 days apart. -    Do not make more than four applications per acre per year. -    Do not make more than two consecutive applications per crop. -      Do not apply more than a total of 8.5 oz of Transform WG (0.266 lb ai o...

As final seed purchases are being made in the Texas Panhandle, here is a brief update on the status of Bt corn. But before your eyes glaze over from the discussion below of new Bts and resistance to older Bts, I want to highlight a publication that makes it easy to tell which toxin packages and herbicide traits are in which type of corn. Dr. Chris DiFonzo at Michigan State University publishes the annual " Handy Bt Trait Table for U.S. Corn Production ", and the 2018 version was posted online today. (I am a contributor to this publication, but Dr. DiFonzo does the heavy lifting.)  In just two pages she lists the types of Bt present in all commercialized corn in the U.S.A., and the table presents the trade names for traits, Bt event, protein(s) expressed, targeted insects and herbicide traits. The 2018 Trait Table also lists the insect x Bt combinations with documented field-failures, confirmed resistance, or cross-resistance. These statements are based on published lab assays...

Insects have developed resistance to the older Bt toxins in cotton and corn on a local or regional scale. A quick look at the situation in the southern U.S.A. finds that in the last two years, resistance has been documented over a large geographic area in cotton bollworm/corn earworm ( Helicoverpa zea ) to the cotton Cry1Ab, Cry1Ac and Cry2Ab2 toxins. In corn, the limited efficacy of Cry1Ab, Cry2Ab2 and Cry1F has slipped from where it was years ago. This year in the mid-south, university personnel are reporting as much earworm damage in Bt corn as in non-Bt corn. The "new" toxin, Vip3a, is highly effective on bollworm/earworm, and seed companies are putting it into new corn hybrids and cotton varieties alongside suites of the older toxins for which resistance has developed. Yes, readers can already see what is wrong with this picture; once Vip3a hybrids and varieties are widely planted, bollworm/earworm will be selected for successive generations on this toxin that now has on...

I am not smart enough to be a Plant Pathologist, and in fact had two courses in it in college and still don't understand it. The classic "disease triangle" taught in pathology says that disease occurs when there is a pathogen, susceptible host and conducive environment. This year we seem to have had a happy triangle for Fusarium species, the causative agents of fumonisins. Not much is known locally about how these fungi interact with our corn, but it is thought that drought stress followed by warm, wet weather, especially at flowering, favor the fungi. Being just an entomologist, I tend to think there is a baseline risk for significant fungal infection based on the susceptibility of the host (hybrid genetics) and environmental conditions. Without insects in the system there will be a given level of fungal growth and fumonisin creation. In my simplistic entomologist's picture, the baseline level is what it is and can vary from year to year, but insect damage can add to...

We are now concluding five straight days of rain on the southern High Plains, but sugarcane aphids are still with us. I spent some time today collecting infested leaves and examining the aphids under a microscope, and I have to report that I can't find any evidence of the fungi that hammered populations on the Gulf Coast. (Although I will keep monitoring the situation.) Most of the aphid colonies I observed looked just fine, and there were some beneficial insects like syrphid fly and lady beetle larvae feeding on them. Dr. Katelyn Kesheimer, IPM Agent in Lubbock and Crosby counties, took 7 Day After Treatment data in a sugarcane aphid efficacy trial yesterday between rain events, and she reported that there was a slight decrease in aphid numbers on the untreated plots, but nothing to write home about. So the rains did not really reduce the number of aphids, but, significantly, the cooler temperatures slowed them down. Aphid development and reproduction is slower in cooler temperatu...