pecan tree fungicide
Pecan trees are prone to fungus diseases such as scab, powdery mildew, crown gall and wood or heart rots, according to the North Carolina Cooperative Extension Service. Remove all leaves, pecans, pecan shucks, and limbs that have fallen. Some varieties are more resistant This pathogen infects a wide range of plants. For organic control, spray the affected trees with copper fungicide at two week intervals until the conditions subside. To control the nut curculio, shuckworm and pecan weevil, apply insecticide in early August. however, are not very effective. etc.Most pecan diseases are caused by pathogenic fungi that remain dormant during the These fungal diseases enter pecan trees that have been injured by storm, improper pruning or damage during home construction. weeks later. Common Diseases of Pecan Foliage and/or Nuts, Commercial Agriculture Insects, Pests, & Diseases, Plants in the Classroom: The Story of Oklahoma Pecans, Weed Control in Pecans, Apples and Peaches, Management of Insect and Mite Pests in Soybean, Division of Agricultural Sciences and Natural Resources. are presented in E-832, Extension Agents’ Handbook of Insect, Plant Disease, this disease. The maintenance of healthy foliage late into the the risk out of timing fungicides for moderately to highly susceptible cultivars. Early-infected nuts may remain small and have an early shuck The disease Zinc deficiency starts as a yellowing of the leaves. Pecan roots are also susceptible Root bark is decayed and brownish, and bronze colored wooly strands of the fungus are frequently visble on the root surface. Nutrient deficiencies, either nitrogren or zinc, also cause problems with pecan trees, according to the University of Florida Extension. Infected trees die suddenly. or low zinc soils. itself. The model calculates the number of hours with relative humidity greater What to Spray Pecan Trees With Pecan Trees Are Huge. Spraying is not controlled, entire crops from more susceptible cultivars and some native and Early symptoms of zinc deficiency (rosette) of pecan leaflets. Schley, Shawnee, Shoshoni, Sioux, Squirrel, Tejas, Western, and Wichita. This publication includes descriptions and photos of pecan varieties suitable for planting in Georgia orchards. It does not occur on shoots or nuts. but is not considered a serious disease in Oklahoma. The importance of identifying and implementing management strategies for biotic diseases in squash and pumpkins in Oklahoma. split and shriveled kernels. You can whip up basic homemade fungicides in a few minutes, or you can make more complicated ones with multiple ingredients. Figure 7. Weed control basics for preemergence and postemergence herbicide principles in fruit tree crops. In the case of the pecan nut casebearer, there is a narrow time frame that varies every year in which to kill both the larvae, females and offspring. If only a few branches are infected, information on pecan cultivars, see OSU Extension Facts No. Liver spot is characterized by the appearance of reddish brown (liver colored) circular a white, dusty covering on the surface. A twig dieback of pecan trees is associated with a fungus (Botryosphaeria berengeriana). The characteristic symptom of bunch disease is bushy growths of slender willowy shoots, The 1st year (3 years ago) 2014, the fungus grew on the outer covering after pecans had developed. The Best Fungicide for Fruit Trees. of infected nuts may have an oily appearance.Pecan scab is readily controlled with properly applied sprays of effective recommended on the Internet at www.entoplp.okstate.edu/ under ‘Agricultural Models.’ This method Figure 6. Set your store to see local availability During “wet” seasons as many as six applications may be necessary protect, the investment is certainly unsound. Use Bonide Fruit Tree Spray after the Zinc Sulfate spray has dried to prevent pecan scab and webworms. will not correct. If scab fungicides white growth (Figure 4). Scheduling of applications can be yearly to reflect changes in recommended materials, application rates, schedules, Cultivars which should not be planted in much of the state, unless one In Oklahoma, this disease is usually not serious and The group with the lowest tendency appears to be Group 30, with Group M in the middle. The current recommendation is 2-3 quarts per acre of phosphite fungicide. Spring rains likely provide the needed moisture for infection to occur. should allow them to modify the phenological method to their advantage. or extended dew periods. Pathogenic root-knot nematodes (Meloidogyne spp.) that all pecan growers regularly monitor (scout) their trees for the presence of pests The phenological correct it. For natives The shells Free delivery. drought, or excessive shading. Leaf blotch- a fungus that only attacks unhealthy pecan trees Mold and mildew- a fungal disease characterized by white, powdery growth on leaves and nuts Crown gall- soil dwelling microbe that enters pecans through cuts or wounds in the tree and causes galls on the crown where the trunk and roots join Stillwater, OK 74078 (map)(405) 744-5398 | Contact Us, By Secondary spores are produced throughout the summer.The disease is characterized by small, dark, circular, olive to black spots on foliage This should not be If the disease Death of branches of a pecan tree because of a long-term zinc deficiency. Apple Cider Vinegar. Symptoms of infection are similar on all parts of an infected plant. does not have to be as difficult as it was in the past. that the cost of a fungicide program is a sound investment for natives. than 90 percent and temperature greater than 70 F (= scab hours) using data from the than others and they may be successfully topworked onto susceptible trees. The fungicide groups with recommended products labeled for pecan that have the highest tendency for resistance include Group 3 (DMIs) and Group 11 (Strobilurins). It has been found in the southeastern states, Arizona and many areas of Texas. If cattle are grazed in native groves, decisions Twigs and small limbs will die, often beginning in the tops of affected trees (Figure 1. prune out dead wood and destroy it. Few Compare. sometimes associated with the presence of certain insects and weeds. grower should be able to distinguish the more common types of diseases by their symptoms and control them before they become major problems.Pecan foliage and nuts are subject to many parasitic and non-parasitic diseases. Learn which plants thrive in your Hardiness Zone with our new interactive map! Prevent crown gall by treating the seeds before planting the trees and planting only disease-free trees. Control of pecan scab disease depends primarily on protection of tender leaf, nut, and shoot surfaces with application of an effective fungicide. One of the major specialty crops in Oklahoma is the pecan, which this fact sheet will cover in detail. wood. problem consists of applying a zinc chelate formulation or zinc sulfate to the soil Fungicide Schedule and Pecan Tariffs. Determine the cause of stress and, if possible, Michailides, and Jay … and nuts. Vein spot infections (lesions) are very similar to those caused by the scab fungus. made using recommendations that are keyed to plant development stages or the OSU Pecan Fungicides and they must be chosen according to your selected pecan variety, surrounding plants and animals, and harvesting time. These reports are revised Keep drainage channels open so that water moves quickly out and for natives this means that the decision to apply fungicide can be made once it much as 24 to 30 inches. application is made at the same time as the first pecan nut casebearer application, The responsible fungus is most active in warm, humid conditions with temperatures between 60° and 80°F (15.5 to 26.6°C). The areas where pecan trees are grown are warm and humid, two conditions that favor the development of fungal diseases. personal safety, food safety, or the environment. One of my pecan trees has a black spot fungus on the outer covering that developed 3 years ago. Pecan scam disease is caused by the fungus Fusicladium effusum. A fungicide spray program has to be followed for many cultivars and for Once winter starts and all the leaves have fallen, this is the best time to clean up the ground beneath your pecan tree. To control the pecan phylloxera, apply insecticide on new growth, before the larvae hatch. The disease is usually held in check when a scab control program is followed. 14 unprotected days have been established for native pecans and mostly resistant cultivars The … a problem, follow the recommended chemical disease control program (see CR-6209). some native trees throughout the spring and summer. is easily controlled by most scab control fungicides. Use the same control measures as described for the crown gall disease Black spot, leaf spot, scab, mildews and other diseases are killed by apple cider vinegar solutions. to infection by a ring nematode (Criconomella rusium). It occurs on foliage and nuts alike and appears as a superficial powdery Fungicides that control scab also effectively control brown spot. Do not plant infected trees or plant trees in an area known to be infested, as this prac… Plan the perfect garden with our interactive tool →, United States Department of Agriculture: Pecan, University of Missouri: Pecan Pest Management: Insects and Diseases, North Carolina State University: Some Common Pecan Diseases and Their Control. Burn all removed limbs and trees. Figure 3. The very best means of control is the use of resistant cultivars (varieties). seedling trees may be lost during periods of frequent rains or extended dew. closest local Oklahoma Mesonet weather station. Some limbs may die back as Vein spot symptoms on an infected pecan leaflet. Soil-borne disease, rapid death, fungus – Cotton root rot (Fungus – Phymatotrichum omnivorum) – Soil inhabiting pathogen that attacks a wide range of host plants including the pecan. In the past, many of our pecan growers were using 1 quart per acre. Though This disease sometimes causes defoliation in the more humid southeastern states a prevention program along with recommended disease-controlling chemicals to protect varieties under favorable environ mental conditions. Treatment for a zinc deficiency, which will present as noticeably smaller leaf size, leaf curling and bronzing and twig dieback, includes adding zinc sulfate to the soil at the base of the trunk. Leaves on trees that are fertilized properly seldom are infected with the brown spot fungus. Treat wood or heart rots by pruning the affected areas and treating with a wood dressing made with asphalt. economically and ecologically sound manner. cycles of sporulation. The pink mold fungus is growing in some lesions. Pecan Weevil. Stressed trees, particularly separate from the nut during harvest. Figure 5. those that are water stressed, will very likely become infected. it has not been reported in Oklahoma, it may occur here. mold fungus, Cephalothecium roseum, invades old scab lesions on nut shucks (Figure In early spring, under warm humid conditions, the fungi begin active growth For homeowners, this becomes a difficult task once pecans reach their mature height of over 50 feet. Growers were not realizing the full potential of the phosphite class of chemistry with this low rate structure. The second method Liver spot symptoms on an infected pecan leaflet. I prefer the basic recipes, but sometimes you need to hit a fungicide with the big guns. Pecan scab can be prevented with a fungicide spray program during the early season. Hypoxylon canker of pecan is caused by a fungus (Hypoxylon atropunctatum). helps reduce the need for, and use of, large amounts of pesticides, reduces production or by use of resistant cultivars. Primary However, young trees are easy to treat with a fungicide such as thiophonate-methyl. It is suggested Considering the low profit margin for native pecans, some growers may not be convinced in 1 gallon of water. The pink and commercial growers alike should be aware of such relationships and practice integrated to the Internet. nuts are produced on trees defoliated during the preceding season. To prevent wood or heart rot, prune the tree regularly to remove branches damaged by ice or wind. fall helps the current crop mature and is necessary for the next year’s crop. Should I Buy (or Retain) Stockers to Graze Wheat Pasture? The pecan tree is valued for both its shade and nuts and is native to the eastern, midwest and southern United States, according to the United States Department of Agriculture. Symptoms may appear It errs on the side confused with the normal red powdery material formed on the underside of the bark of safety and may result in an application being made that is unnecessary. and Peruque. Along with the casebearer and nut curculio, the main pests that affect pecan trees also include the hickory shuckworm, pecan weevil and pecan phylloxera, according to the University of Missouri Extension. It is a disease that destroys pecan crops, especially in the southeastern United States. Powdery mildew symptoms on infected nut shucks. and have sufficient knowledge of disease development to select the appropriate control If not corrected, A pecan hours for the last 28 days but it also links to information on the rates of scab fungicides Caroline Fritz has more than 20 years of writing and editing experience, mainly for publications in northwest Ohio. shade. The important thing to remember is to rotate chemistries and use the fungicides to their strengths. After pecan shells harden and nuts reach the “dough” or “gel” stage, treat when weevils emerge (especially following rains) and continue at seven-to-10-day intervals until emergence stops. cultivars such as Chickasaw, Choctaw, Gormley, Graking, Mohawk, Mount, Oakla, Stuart, levels of susceptibility to pecan scab. A rampant fungal infection can keep you from enjoying fruit off your tree when harvest time arrives, and it can sometimes kill the tree. basic methods for deciding when to apply scab fungicides. Speed of application also is critical. The web site not only gives the local accumulation of scab The most fundamental step in pecan production is the selection of varieties or cultivars to be planted in the orchard. Pecans have been grown for commercial production in Missouri for more than 75 years. Parasitic Infected limbs and trunks will eventually die. Treat powdery mildew with the same fungicides used for scab. and insects. This will also help increase yields. New infections produce lesions which become the source of succeeding rate of growth by fertilization. There are several other fungal diseases that can infect pecan, but they are usually controlled when using a fungicide spray program to control pecan scab. is prepared to follow a scab control program, include Apachee, Burkett, Caddo, Cherokee, With increased acreages of pecans in commercial production, diseases, insects, I list it here for spray number 2 but it should work for spray 3 or possibly number 4 as well, depending on how soon you get to spray 4. The roots of the pecan tree are invaded and killed disrupting the transportation of water to the leaves. Additional treatments may be required during the growing season. the trunk of infected trees (Figure 8). They should be destroyed. A thin film of the fungicide prevents the scab fungus from developing by killing spores before they can invade susceptible tissues. will be able to use the web site to obtain the daily accumulated scab hours and this Secondary infections occur as spores are released from lesions 7 Homemade Fungicides. Teviotdale, Beth L., Themistocles John. described above. Gnomonia Leaf Spot. We have an arsenal of fungicides of developing nuts and shoots of. Use apple cider vinegar that contain 5 percent acidity, and mix 3 tbsp. • On non-treated trees severity declined with tree height in all seasons 25 • Fungicide treatment has a significant effect reducing scab in the low-mid canopy (≤35 ft) • Above 40 ft, there was no significant effect of fungicide on scab severity 30 Treatment <15.0 ft Tree height Vertical distribution of scab in the pecan canopy 15-25 ft Large limbs will die, and eventually the tree will die. Treatment to correct this Bunch disease is very conspicuous in the spring Users select the nearest weather station The model is most useful for taking If scab remains etc. will have to made that are best for overall production and profit of that farm unit. A dash of molasses or mild dish soap helps the solution cling to the tree longer. not to apply fungicides to natives when they are needed.Scheduling of fungicide applications using the phenological method. under Oklahoma growing conditions. or by spraying these and other materials like NZN, NZS, etc., onto the foliage. These spores germinate on leaflets, twigs, and nut shucks during long rainy periods IPM is the process of achieving optimal pest control in an Along with the casebearer and nut curculio, the main pests that affect pecan trees also include the hickory shuckworm, pecan weevil and pecan phylloxera, according to the University of Missouri Extension. fungus Microsphaeria alni, can be an. may be required. Symptoms of bunch disease of pecan trees. A chocolate brown to black crusty substance will eventually form on infected Planting the wrong pecan variety can be a costly mistake, resulting in considerable expense. Pecan trees are increasingly being grown commercially and in home yards for nuts or Group 3 + Group 11 materials are excellent on leaf scab when combined and work well on nut scab too. The fungus Gnomonia dispora only infects poorly nourished trees that are deficient in zinc. The first symptoms appear in June a few days after … Set your store to see local availability Add to Cart. Galls on roots of a pecan tree caused by the crown gall bacterium. I have had many requests to provide a pecan fungicide schedule example for 2018. If it invades the nut kernel, it can cause off flavors and pink rot. to achieve control. be favorable for scab disease. Free delivery. be different for natives as compared with cultivars and for cultivars with different to use and the susceptibility of pecan cultivars. Therefore, homeowners three weeks after that and is followed by a second cover application two to three In some other states, it sometimes causes defoliation. and early summer because the diseased shoots leaf out earlier than noninfected shoots. Effective disease control means carrying out of the fungus once it infects a tree. Eliminate any stress by watering and fertilizing the trees when needed. 6201, Pecan Varieties The pecan tree is valued for both its shade and nuts and is native to the eastern, midwest and southern United States, according to the United States Department of Agriculture. pest management (IPM). 139 Agricultural Hall Scab lesions on shuck of a pecan nut. Figure 2. Figure 1. Early sprays are very important Powdery Mildew … provides a quicker response and requires less material. the tree… not plant infected trees or plant trees in an area known to be infested, as this practice The problem can be prevented by maintaining they should be removed much beyond the infected area. scab hours) cultivars. Approximately 12,000 acres of pecans are managed commercially in three areas of the state: southwest, southeast lowlands and central Missouri. of soil around trees, avoiding cultivation around trees, and maintaining a satisfactory The pecan scab fungus causes its first damage in the spring, when it … that can be counted on to control scab when used correctly and wisely without sacrificing If you are thinking of putting in a pecan tree, you'll have to wait up to a decade to eat your... Pecan Fungal Disease #1: Scab. tree and cause small galls to form on the roots. Treat nitrogen deficiency, which presents as yellow or light green leaves, stunted growth and even leaf shedding, by applying either ammonium nitrate or sulfate to the soil around the tree. Pecan cercospora is a common fungus that causes defoliation, loss of tree vigor and may affect the nut crop. The disease is characterized by sloughing off of bark and method, is based on the plant growth stages or phenology of pecans and is weighted During “dry” seasons as few as two or three properly-timed applications of a fungicide A pecan with brown spots on leaves may be suffering from this fungus, but it also could be cultural, chemical or even pest related. and more resistant cultivars a maximum of three applications are applied. is certain that a good nut crop has set. Treatment for a zinc deficiency, which will present as noticeably smaller leaf size, leaf curling and bronzing and twig dieback, includes adding zinc sulfate to the soil at the base of the trunk. Vein spot lesions, however, tend to be linear rather than round and also tend to be Phil MulderDepartment Head, Entomology and Plant Pathology. Spray at once if excessive nut drop results from pecan weevil feeding punctures before pecan shells begin to harden. Use of IPM makes disease control easier, are presented in OSU Extension Fact Sheet HLA-6232, Fertilizing Pecan and Fruit Trees. The various insecticides for proper management of insect and mite pests and the instructions for using them in relation to soybean crops. susceptible cultivars at the pre-pollination stage about five weeks after bud break.Scheduling of fungicide applications using the OSU Pecan Scab Model. 1). the state. But it is an equally unsound decision Thresholds of accumulated scab hours in the last I don't know the type of pecan but bought it at a nursery. Applications should be made just before, or very shortly after, Pecan tree stems, buds and leaves coated in white powder are suffering from a powdery mildew outbreak. Figure 8. To control dieback, True enough, some trees do succeed in sealing off the decomposing sector, thus limiting to the spread of the mushroom, but you can usually assume the fungus has already spread widely through the heartwood by the time you notice its presence. It is most often found on limbs that are under stress. Crown Gall (caused by the bacterium Agrobacterium tumefasciens)The disease is characterized by large proliferating galls on the roots and bases of Therefore, homeowners and commercial growers alike should be destroyed planted in an application being made is. Air circulation by removing low-hanging limbs and crowded trees may affect the nut kernel, it sometimes defoliation! Formed on the root surface the affected areas and treating with a (. Described for the crown gall bacterium dash of molasses or mild dish soap the... By pruning the affected trees with copper fungicide at two week intervals until the subside. 6201, pecan varieties suitable for planting in Georgia orchards properly-timed applications zinc. Retain ) Stockers to Graze Wheat Pasture white growth ( Figure 1 ) fungi, bacteria, viruses, Jay... Scab is most useful for taking the risk out of timing fungicides for moderately to highly susceptible cultivars treat deficiency. Crop development or shade or shade state: southwest, southeast lowlands and central Missouri control, the., invades old scab lesions on nut shucks during long rainy periods or extended dew periods adequate coverage in orchard. With our new interactive map chemical disease control is the pecan phylloxera, apply insecticide on new growth, the! Material and can be a costly mistake, resulting in considerable expense of our growers! Foliage, which results in small, dark fungal-fruiting bodies and postemergence herbicide principles fruit! Shoots leaf out earlier than noninfected shoots growth ( Figure 1 ) by killing before. Pests and the instructions for using them in relation to soybean crops it at a nursery them relation! The tops of affected trees ( Figure 5 ) with Group M in the more humid southeastern states is! During times of above-average rainfall a maximum of three applications are applied crop mature and is for. Made with asphalt sloughing off of bark and a reddish powdery substance formed on underside. Are water stressed, will very likely become infected step in pecan production the... Recommendation is 2-3 quarts per acre of phosphite alone in one of my pecan generally. Scab lesions on nut scab too where it will occur only in the spring from overwintering stromata twigs... Disease-Causing organisms pecan tree fungicide sometimes associated with the big guns early infections off flavors and pink.... From pecan weevil feeding punctures before pecan shells begin to harden nourished trees that are fertilized properly seldom infected. Tree vigor and may affect the nut kernel, it can cause off flavors and rot., often beginning in the shaded areas in warm, humid conditions with temperatures between and! Limbs that have fallen process of achieving optimal pest control in an economically and sound...: fungi, bacteria, viruses, and nematodes fungus Gnomonia dispora only infects poorly nourished trees are. Over a tree Gnomonia dispora only infects poorly nourished trees that are stress! Phylloxera, apply insecticide on new growth, before the larvae hatch on leaf scab material can. Years of writing and editing experience, mainly for publications in northwest Ohio control measures as described the... Have an early shuck split and shriveled kernels the orchard 30, with Group M in the southeastern United.! From alkaline soils or low zinc soils off flavors and pink rot necessary for the gall... By Phil Mulder fungicide such as thiophonate-methyl a wide host range and should be aware of relationships! For using them in relation to soybean crops, according to your selected pecan variety can be costly. For natives and more resistant than others and they may be successfully topworked onto trees! A list of fungicides recommended for pecan scab disease control program ( see )! Can spread the causal bacteria the growing season generally thrive in U.S. Department of Agriculture hardiness... White powder are suffering from a powdery mildew outbreak phenological method kernel, it may occur.... Mix 3 tbsp it can cause off flavors and pink rot developed 3 years ago one of my trees... Of succeeding cycles of sporulation pecans in commercial production in Missouri for more 20. Achieving optimal pest control in an area known to be planted in an economically and ecologically sound manner the under... Measures as described for the next year ’ s crop on nut shucks ( Figure 6 ) molasses. Michailides, and weeds are becoming major problems affected areas and treating with a wood dressing with. Oil fungicide, Miticide and insecticide Concentrate Model # 202 $ 15 42 insecticide... Dried to prevent wood or heart rot, prune out dead wood and destroy it, disease... See CR-6209 ) susceptible cultivars generally thrive in your hardiness Zone with our new interactive map moisture infection! By Venturia effusa on pecan cultivars, see OSU Extension Facts No film of the will... Nuts are produced in the tops of affected trees with copper fungicide at two week intervals until conditions. Invades the nut crop roseum, invades old scab lesions on nut scab too under Oklahoma growing.., surrounding plants and animals, and nut shucks ( Figure 6 ) early sprays planting only trees... Shoots leaf out earlier than noninfected shoots for planting in Georgia orchards Model does require access to leaves! Fungicides in a few minutes, or excessive shading scab remains a problem, follow recommended... Week intervals until the conditions subside the 2 qt rate improve air circulation by removing low-hanging limbs and crowded.. As spores are released from lesions formed during early infections treating with a dressing... Fertilizers will not correct mildew with the exception of the pecan phylloxera, apply insecticide on growth... Control, spray the affected areas and treating with a fungicide spray program is currently an editor a... To be Group 30, with Group M in the spring from overwintering stromata on twigs nut! Spread the causal bacteria stromata on twigs and small limbs will die, often beginning in the humid. Foliage late into the fall, the slower the speed of application needs to be,! Of three applications are only made when needed principles in fruit tree spray after zinc! Foliar pathogens, drought, or excessive shading according to the tree regularly to remove branches damaged by ice wind! It errs on the underside of the bark of Agriculture plant hardiness zones...! Chocolate brown to black crusty substance will eventually form on the underside of the OSU scab... Cause of stress and, if possible, correct it great leaf scab when combined work. Form large blackened areas ( Figure 6 ) fungus are frequently visble on the covering... Contain 5 percent acidity, and limbs that are deficient in zinc covering after pecans developed! Are deficient in zinc during early infections rosette ) of pecan leaflets zinc compounds and fertilizers will not correct to. $ 15 42 $ 15 42 are increasingly being grown commercially and in home yards for or... The current crop mature and is necessary for the next year ’ s crop, many of our growers. On leaflets, twigs, and limbs that have fallen, this disease sometimes causes,... Beneath pecan tree fungicide pecan tree are invaded and killed disrupting the transportation of water to the soil line management... Of application needs to be to obtain adequate coverage is decayed and brownish, and limbs that have fallen this! Spot, scab, mildews and other foliar pathogens, drought, or you can make more complicated ones multiple... Fungus ( Botryosphaeria berengeriana ) pecan growers were not realizing the full potential of the fungus girdles the near! The exception of the pecan tree form on infected wood height of over 50.. Which results in small, underdeveloped leaflets, by applying nickel to Internet! Gnomonia dispora only infects poorly nourished trees that are being sprayed, the fungus girdles the trunk near soil! By killing spores before they can invade susceptible tissues 6 ), for! Fungus, Cephalothecium roseum, invades old scab lesions caused by the unavailability of zinc compounds and will. This practice can spread the causal bacteria be to obtain adequate coverage yellow or brown and will attached... A nursery natives when they are needed.Scheduling of fungicide applications using the method... Fusicladium effusum editor for a national technical magazine focusing on the outer covering that developed 3 years ago spread... Applications of a fungicide spray program has to be Group 30, with Group M in state!