WHAT S HAPPENING? The University of Tennessee/Agricultural Extension Service Entomology & Plant Pathology - EPP #60

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1 WHAT S HAPPENING? The University of Tennessee/Agricultural Extension Service Entomology & Plant Pathology - EPP #60 15 June 2007 TOBACCO FUNGICIDES AND SP91 by Darrell Hensley When preparing portions of SP91, I must have used the older version of the document stored on my PC. This was a big mistake on my part, because SP91 should have included our recommendations for Quadris. Quadris fungicide is labeled to control frog-eye leafspot (Cercospora nicotianae), blue mold (Peronospora tabacina) and target spot (Rhizoctonia solani). Quadris is labeled at 6-12 fl.oz. per acre, but we recommend that no more than 8 fl oz per acre be used in most circumstances. Quadris is limited to four applications per crop with no more than one application made after topping, although that application can be made as late as the day before harvest. It should be applied with sufficient water volume for adequate coverage and canopy penetration. No more than 0.52 lb. a.i./a per season of azoxystrobin-containing products should be applied to tobacco. Quadris should not be tank mixed with Thiodan. Avoid tank mixing Quadris with insecticides formulated as ECs or containing high amounts of solvents, because it may cause some crop injury. Do not apply more than one application of Quadris or other Group 11 fungicide before alternation with a fungicide that is not in Group 11. For target spot and frogeye control, the only labeled fungicide that is suitable is Dithane. For blue mold control, several labeled fungicides are effective. Quadris may enhance weather flecking. This has not been reported to affect yield and quality. For blue mold control, Quadris applications should begin prior to disease development or at first indication that blue mold is in the area. If blue mold is present in the field initiate application with Acrobat and Dithane DF prior to Quadris application. Remember, if Quadris is applied more than once, it must be followed by another labeled fungicide.. SOME MAPLE PROBLEMS CAN BE PREVENTED by Alan Windham Many times I have read of the dangers of placing mulch against the trunk of a young tree. It will cause rot, decay or worse, so they say. However, in all my years of looking at problems of young trees I have yet to see decay that I felt was attributable to mulch. Which makes sense, if you consider that no one is in the forest pulling leaf litter, bark, twigs (mulch in a sense) away from the trunks of young trees and they prosper. Problems I do see include: planting too deep, too much mulch, phytophthora crown rot (not mulch induced), over watering, under watering, mechanical wounds, borer damage, strings and straps not removed at planting leading to girdled trunks and girdling roots. Maples are particularly prone to initiate roots around the trunk if planted too deeply or if mulch is placed against the trunk (Figure 1). Leave a young root growing around the circumference of a tree s trunk and it will as effectively girdle it as wire, string or a nylon strap left at planting. It may take several years, but it will 1

So the take home message is: mulch probably doesn t cause decay when placed around the trunk of a tree, but it does obscure any young roots that may cause problems in a few years. Figure 1.

2 happen. The trunk of a semi-mature maple with girdling roots will have no visible buttress roots and look somewhat like a telephone pole (Figure 2). Other symptoms may include a thin canopy and leaf scorched leaves. If found before the girdling starts, encircled roots can be removed with a chisel and a mallet, generally with no harm to the tree. So the take home message is: mulch probably doesn t cause decay when placed around the trunk of a tree, but it does obscure any young roots that may cause problems in a few years. Figure 1. Young root growing around the trunk of a red maple. Figure 2. Advanced damage from a girdling root. Notice the absence of buttress roots. FIELD CROP UPDATE by Russ Patrick Trap Catches May 24 to June 4, 2007 Benton 33 Lake 52 Obion 208 Weakley 38 Carroll 31 Charleston, Mo 33 Stored Grain: I have been asked recently what materials can be used on stored wheat in grain bins. First of all clean up the bin before filling. Tempo Ultra SC can be used only on the empty bin then you can fill it with the grain. If you wish to use a grain protectant we recommend Storcide II for use on the grain itself. It is the only one that is being recommended as you bin the grain. Rates: 12.4 ounces in 5 gallons water/1000 bushels. The protectant is added to the grain stream as it goes into the bin. You will not get complete protection but it will reduce the number of infestations occurring during storage. Costs are about 3 to 4 cents a bushel which is not bad for keeping insects out of your grain. 2

3 VEGETABLE INSECTICIDE UPDATE by Frank A. Hale Be sure to get a copy of the 2007 Commercial Vegetable Disease, Insect and Weed Control guide, PB1282. Since this publication is updated each year, there are often many new chemical recommendations. Several of these pesticides are fairly new and some even have unique modes of action. In PB1282 on page 91, a number of these new products are recommended for whitefly control on tomatoes. Acetamiprid (Assail 30 SG) and dinotefuran (Venom 70 SG) are both neonicotinoid insecticides (mode of action group 4) recommended for whitefly control. You are probably more familiar with the neonicotinoid insecticides thiamethoxam (Platinum 2 SC) or imidacloprid (Admire 2 F, Admire Pro 4.6 F, Provado 1.6 F), that have been in our recommendations for several years, although Admire Pro 4.6 F is new addition. The neonicotinoid class of insecticides are generally very systemic and effective in controlling many types of insects, especially sucking insects such as whiteflies and aphids. Some of the neonicotinoids also are effective on sawflies, leaf feeding beetles such as cucumber beetles and Colorado potato beetles, and other listed pests. Many of these products can be applied to the soil usually around planting. Root uptake moves the product up to the new growth for long lasting protection from insects. Some of these products can be applied to the soil and also as a foliar spray. It is generally recommended that you only make one type of application, not both, in a given season for resistance management purposes. Provado 1.6 F and Assail 30 SG are labeled only for foliar application. The insecticide is rapidly absorbed by the plant tissue and quickly moves via systemic translaminar activity to protect the entire leaf. Foliar applications of neonicotinoids generally protect the foliage for a much shorter period of time than the soil applied ones, so repeat foliar applications may be required. Another new product for whitefly control, spiromesifen (Oberon 2 SC), is also an effective miticide with a unique mode of action (inhibitors of lipid biosynthesis, mode of action group23). Buprofezin (Courier 40 SC) is an insect growth regulator (inhibits chitin biosynthesis in the immature insect) with a unique mode of action (group 16). Another insect growth regulator (juvenile hormone mimic which prevents molting from the immature to the adult stage, mode of action group 7) that has been available for several years is pyriproxyfen (Knack 0.86 EC). All this new chemistry should give the grower a wider assortment of pest control tools. For resistance management purposes, rotate insecticides not just by class, but by mode of action since some insecticide classes are in the same mode of action group. PLANT & PEST DIAGNOSTIC HIGHLIGHTS by Bruce Kauffman We received 56 samples from May 31 to June 11, 2007 including 43 samples via the UT Diagnostic Web Site. TOBACCO and FIELD CROPS : Target leaf spot of narrow leaf tobacco; thrips on tobacco; soreshin (Rhizoctonia species) on tobacco; hay damaged by dry weather; stem disease of tobacco. FRUIT and VEGETABLES : Roundup herbicide damage on tomato; southern blight of tomato; leaf spot of cucumber and squash; herbicide damage to cabbage, peppers, tomato and cantaloupe; coniothyrium cane blight of black raspberries; root rot of apple; tomato ring spot virus of Apacha blackberry; tomato spotted wilt virus of tomato; common bean mosaic virus on snap 3

4 beans; tomato nutrient imbalance causing fruit breakdown; bacterial leaf spot of peach; excessive levels of potassium and phosphorus following over-fertilization of tomatoes. INSECTS and MITES : Ugly nest caterpillar on Yoshino cherry; leaf tier caterpillar on Shumard oak; calico scale on maple, redbud and sweetgum; spruce mites and rust mites on hemlock; four-lined plant bug on mint and geraniums; spittlebugs on Leyland cypress; peach tree borer and American plum borer on purple plum; pseudanthonomus weevils on flower buds and fruit of apple and cherry. In and around the house : Common honey bee; moth fly; wasp or bee in wood-boring beetle gallery; stoneflies; jumping spider. ORNAMENTAL : Phyllosticta leaf spot and fungal canker of Japanese maple; azalea lace bug on rhododendron; phylloxera leaf gall of pecan; transplant shock on boxwood; fungal canker of Kwanza cherry; southern stem rot of hosta; cercosporidium needle blight of Leyland cypress; decline of sugar maple; Ips bark beetles and procerum root disease of eastern white pine; seiridium canker of Leyland cypress; phytophthora root rot of Vinca minor and petunias; powdery mildew of rose and associated plants; drought-initiated decline and death of eastern redcedar; coniothyrium leaf spot of ivy; yew root decline caused by excessive moisture; juniper winter injury. TURF : Zoysiagrass browning due to dry weather; bermudagrass smut (Ustilago cynodontis); anthracnose of bentgrass. 4

5 OTHER UT NEWSLETTERS WITH PEST MANAGEMENT INFORMATION Fruit Pest News Tennessee Crop and Pest Management Newsletter This and other "What's Happening" issues can be found at Precautionary Statement To protect people and the environment, pesticides should be used safely. This is everyone's responsibility, especially the user. Read and follow label directions carefully before you buy, mix, apply, store or dispose of a pesticide. According to laws regulating pesticides, they must be used only as directed by the label. Disclaimer This publication contains pesticide recommendations that are subject to change at any time. The recommendations in this publication are provided only as a guide. It is always the pesticide applicator's responsibility, by law, to read and follow all current label directions for the specific pesticide being used. The label always takes precedence over the recommendations found in this publication. Use of trade or brand names in this publication is for clarity and information; it does not imply approval of the product to the exclusion of others that may be of similar, suitable composition, nor does it guarantee or warrant the standard of the product. The author(s), the University of Tennessee Institute of Agriculture and University of Tennessee Extension assume no liability resulting from the use of these recommendations. Visit the UT Extension Web site at 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

Pest Management in Vegetable Gardens. Pam Brown Extension Agent Emeritus, Gardening Coach Pampered Gardeners, LLC

Pest Management in Vegetable Gardens Pam Brown Extension Agent Emeritus, Gardening Coach Pampered Gardeners, LLC pamperedgardeners@gmail.com Pest Management Involves: Providing proper cultural practices