On Friday, October 15, 2010 the Environmental Protection Agency (EPA) announced that Movento (spirotetramat) has been registered, for a second time. Movento was first registered by EPA in June, 2008, but as you likely recall, EPA issued a cancellation order for the Movento registration in April, 2010 that made it unlawful for the manufacture (Bayer CropScience) to sell or distribute the product. However, the cancellation order allowed for the use, sale or distribution of existing supplies of Movento in possession of retailers, distributors and end-users under the provisions of the previously-approved label. The previous Movento registration was terminated because of a judicial action related to a procedural failure on the part of the EPA (failure to publish a notice of receipt of the spirotetramat registration application in the Federal Register). The new registration has been anticipated for several months, and a statement issued by the EPA's Office of Pesticide Programs said After evaluating the application for registration and comments received from the publication of the notice of receipt for registration, EPA has determined that spirotetramat does not pose an unreasonable risk of adverse effects to human health or the environment if used according to the label directions and, as such, meets the Federal Insecticide, Fungicide, and Rodenticide Act standard for registration. Spirotetramat is now registered for use on citrus, grapes, pome fruit, stone fruit, tree nuts, hops, Christmas tree plantations, and certain vegetables, including potatoes. This new registration will be available in the marketplace for the next growing season (see this link)." It is our understanding that pending state approval by the Arizona Department of Agriculture, local growers may purchase inventory and use Movento under the new label. For more information on the new Movento registration please view this press release from Bayer CropScience.
This study was conducted at the Yuma Valley Agricultural Center. The soil was a silty clay loam (7-56-37 sand-silt-clay, pH 7.2, O.M. 0.7%). Variety: Deluxe (HMX2595) was seeded, then sprinkler-irrigated to germinate seed on March 20, 2024on 84 inches between bed centers. All other water was supplied by furrow irrigation or rainfall. Treatments were replicated five times in a randomized complete block design. Each replicate plot consisted of 25 ft of bed. Treatment beds were separated by single nontreated beds. Treatments were applied with a tractor-mounted boom sprayer that delivered 50 gal/acre at 100 psi to flat-fan nozzles spaced 12 in apart.
Spray treatments were done on 05-21-2024, 05-31-2024, 06-07-2024 and 06-14-24. Powdery mildew was first seen on 06-05-24. Please see excel file for additional details.
Disease severity of powdery mildew (caused by Sphaerotheca fuliginea and S. fusca) severity was determined 6-17-2024 by rating 10 plants within each of the four replicate plots per treatment using the following rating system: 0 = no powdery mildew present; 1 = one to two mildew colonies on leaves ;2 = powdery mildew present on one quarter of leaves; 3 = powdery mildew present on half of the leaves; 4 = powdery mildew present on more than half of leaf surface area ; 5 = powdery mildew present on entire leaf. These ratings were transformed to percentage of leaves infected values before being statistically analyzed.
The data in the table illustrate the degree of disease control obtained by application of the various treatments in this trial. Most treatments significantly reduced the final severity of powdery mildew compared to nontreated plants. Quintec, Merivon, Tesaris, Luna Sensation, and V6M-5-14 V gave the best disease control. Phytotoxicity symptoms were not noted for any treatments in this trial.
Controlling Fusarium Wilt of Lettuce Using Steam Heat – Trial Initiated
Earlier this week, we initiated a trial examining the use of band steam for controlling Fusarium wilt of lettuce. The premise behind this research is to use steam heat to raise soil temperatures to levels sufficient to kill soilborne pathogens. For Fusarium oxysporum f. sp. lactucae, the pathogen which causes Fusarium wilt of lettuce, the required temperature for control is generally taken to be > 140°F for 20 minutes. Soil solarization, where clear plastic is placed over the crop bed during the summer, exploits this concept. The technique raises soil surface temperatures to 150-155˚F, effectively killing the pathogen and reducing disease incidence by 45-98% (Matheron and Porchas, 2010).
In our trials, we are using steam heat to raise soil temperatures. Steam is delivered by a 35 BHP steam generator mounted on a custom designed elongated bed shaper (Fig. 1). Preliminary results were encouraging. The device was able to increase the temperature of the top 3” of soil to over 180°F at a travel speed of 0.5 mph as shown in this video of the machine in action (shown below). These temperatures exceed that of those known to control pathogens responsible for causing Fusarium wilt of lettuce (> 140°F for 20 minutes).
Stay tuned for final trial results and reports on the efficacy of using steam heat to control Fusarium wilt of lettuce.
If you are interested in evaluating the technique on your farm, please contact me. We are seeking additional sites with a known history of Fusarium wilt of lettuce disease incidence to test the efficacy and performance of the device.
References
Matheron, M. E., & Porchas, M. 2010. Evaluation of soil solarization and flooding as management tools for Fusarium wilt of lettuce. Plant Dis. 94:1323-1328.
Acknowledgements
This project is sponsored by USDA-NIFA, the Arizona Specialty Crop Block Grant Program and the Arizona Iceberg Lettuce Research Council. We greatly appreciate their support.
A special thank you is extended to Cory Mellon and Mellon Farms for allowing us to conduct this research on their farm.
Weeds are one of the most visible of all agricultural pests. They can’t move or hide and once established often stick up over the crop. Just one weed in a 10 acre field is annoying to look at. With insects and diseases, the damage is often more visible than the pest. That is not the case with weeds. A moderate weed infestation is approximately 10 weeds per square foot. If a herbicide produces 90% control, that leaves 1 weed per square foot or 43 weeds per acre. Without an untreated check, this can look like the herbicide failed! It is easy to leave an untreated spot in a field and it is well worth doing. Many applicators do so unintentionally because of skips, powerlines and other causes. They help determine crop injury and weed control. Here are some examples of what various levels of control looked like from one of our cole crop trials:
Corn earworm:
CEW moth counts increased in the Rol and Dome Vallley areas, above average for this time of year.
Beet armyworm:
Trap counts low; lower than average compared to previous years.
Cabbage looper:
Cabbage looper counts increased in most traps and about average for this time of season.
Diamondback moth:
DBM moths counts increased in most areas. About average for this time of the year.
Whitefly:
Adult movement negligible, typical for mid-winter.
Thrips:
Thrips adult counts remain low, likely in response to rainfall in late December. Currently, numbers are below average compared with previous years.
Aphids:
Aphid movement increased significantly in the past two weeks, particularly in North Yuma and Gila Valleys. Highest numbers we’ve seen in 11 years.
Leafminers:
Adults remain low in most locations, average for January.