Fruit Pest News. Volume 10, No. 5 April 30, 2009

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1 Volume 10, No. 5 April 30, 2009 An online newsletter whose goal is to provide all interested persons with timely information on diseases and insects of commercial fruit and vegetable crops in Tennessee. Text appearing in blue or red can be clicked to link to other web sites. Be aware that much of the linked information is produced in other states and may not be applicable to Tennessee. In This Issue: 1. Current Conditions and First Reports 2. How to Adjust a Spray Program During Rainy Weather Methyl Bromide Critical Use Exemption Rule Announced 4. Black Cutworm Update 5. Tufted Apple Budmother 6. Pheromone Trap Catches and Biofixes 1. Current Conditions and First Reports Showers and thunderstorms are in the picture throughout the 10-day forecast. It could be a challenging period for pest control. See the following article regarding the need for re-application of sprays. First reports for the year during the past week: Phomopsis cane and leaf spot and anthracnose of grape - April 27, Davidson County; fire blight and cedar-apple rust of apple - April 27, Davidson County; powdery mildew (Erysiphe cichoracearum, not the mildew that we see in the field, Podosphaera xanthii) of greenhouse cucumber - April 27, Davidson County. 2. How to Adjust a Spray Program During Rainy Weather Thunderstorm activity is expected throughout the 10-day forecast. Such weather is no friend of a disease and insect control program. Not only is the wet weather conducive to disease development, but the frequent rains remove chemical and biological control products from the plant. Shorter spray intervals will be necessary. A frequent question is: How short? When it's raining almost every day, it can be difficult to find a chance to spray. The following rule of thumb may help you decide when to make your next spray application during rainy weather. It's very general, but should maximize pest control under the conditions, while minimizing excessive spraying. Amount of rain since last spray: Less than 1 inch - Make no changes in spray schedule plans; 1 to 2 (1 of 5)12/6/2012 4:34:11 AM

2 inches - Shorten the remaining time before the next spray by one-half*; More than 2 inches - Apply the next spray as soon as the ground allows. *Example: You plan a 10-day spray schedule and 1.5 inches of rain falls 4 days after an application. Make the next application at 7 days, rather than 10. Note: This guide only applies to non-systemic products. Systemic products, including those with translaminar activity, are largely protected from wash-off. If tank mixing a non-systemic with a systemic, e.g., captan plus Quadris, only the non-systemic material should be re-applied if rain causes a shortening of the spray interval. (SB) Methyl Bromide Critical Use Exemption Rule Announced EPA has released the Critical Use Exemption decision for methyl bromide use in Growers from Tennessee and other southeastern states will be able to use methyl bromide on cucurbit, tomato, pepper, strawberries for fruit, strawberry nursery, and forest nursery sites. However, the allowed amount is rather small, pursuant to the phaseout program. The critical use level for the U.S. in 2009 is 16.7% of the 1991 methyl bromide consumption baseline of 25,528,270 kg. Most of this will come from existing stocks. (SB) 4. Black Cutworm Update Many of the cutworms being found appear to be black cutworms. Contrary to what was stated in the previous newsletter, they do overwinter as pupae in Tennessee. Dr. Scott Stewart, Extension field crops entomologist in Jackson, suspects that some black cutworms might even overwinter as larvae since he has noted newly planted corn being attacked as early as April in past years. (FH) 5. Tufted Apple Bud Moth The tufted apple bud moth (TABM) feeds on leaves and surface feeds on the fruit. This important leafroller has two generations per year. It is helpful to maintain a clean orchard floor, especially in the spring before bloom. The overwintering larvae feed on certain broadleaf weeds and new apple sucker growth. The biofix for this moth was April 24 at the Putnam County orchard location. For control of first generation TABM larvae when population densities are sufficiently high or if a short residual insecticde is used, two insecticide applications per generation may be needed. Make the first (2 of 5)12/6/2012 4:34:11 AM

3 application at about 10 percent egg hatch (800 Degree Days [DD] after biofix), and a second application 14 days later. When TABM populations are low or if using a long residual insecticide (Intrepid, Delegate, Altacor, or Voliam Flexi), one application per generation should be made anytime between 800 to 1,200 DD. These long residual insecticides are very effective at reducing TABM populations to very low numbers. (FH) 6. Pheromone Trap Catches and Biofixes (FH) Nashville (Davidson County) Pheromone Trap Catches for 2009 Oriental fruit moth (OFM), redbanded leafroller (RBLR), obliquebanded leafroller (OBLR), codling moth (CM), grape berry moth (GBM), variegated leafroller (VLR), black cutworm (BCW), diamondback moth (DBM), armyworm (AW), beet armyworm (BAW), squash vine borer (SVB), fall armyworm (FAW) 3-13 (Put out RBLR trap) OFM RBLR OBLR CM GBM VLR BCW DBM AW CL BAW SVB FAW * (put out BCW trap) 3-31 (put out OFM, CM, VLR, OBLR traps) 4-2 4** (put out AW trap) 4-8 (put out GBM, DBM, BAW, FAW, SVB, CL traps) *** (3 of 5)12/6/2012 4:34:11 AM

4 * Biofix for RBLR in Davidson County estimated as prior to March 20 (trap not out early enough). **Biofix for OFM in Davidson County was April 2. ***Biofix for GBM in Davidson County was April 13. Putnam County Pheromone trap Catches for 2008 Tufted Apple Bud Moth (TABM) OFM RBLR OBLR CM VLR TABM * (put out OBLR, TABM traps) (put out OFM trap) (put out CM trap) ** *** *Biofix for RBLR in Putnam County estimated as prior to March 16 (trap not out early enough). **Biofix for CM in Putnam County was April 20..**Biofix for TABM in Putnam County was April 24. The URL is: Contacts: Steve Bost, Professor and Extension Plant Pathologist scbost@utk.edu (4 of 5)12/6/2012 4:34:11 AM

5 Frank Hale, Professor and Extension Entomologist Both authors available at: fax Soil, Plant and Pest Center 5201 Marchant Drive Nashville, TN Copyright 2009 The University of Tennessee. All rights reserved. This document may be reproduced and distributed for nonprofit educational purposes provided that credit is given to University of Tennessee Extension. Programs in agriculture and natural resources, 4-H youth development, family and consumer sciences, and resource development. University of Tennessee Institute of Agriculture, U.S. Department of Agriculture and county governments cooperating. UT Extension provides equal opportunities in programs and employment. (5 of 5)12/6/2012 4:34:11 AM