PEANUTS: <\/strong>Getting lots of questions these days about late-season peanut disease problems.\u00a0 Just a few thoughts.\u00a0 \u00a0 Three weeks to go until you dig the peanuts and little-or-no disease in the field?\u00a0 I wouldn\u2019t put out any more fungicides unless there is threat of a hurricane or tropical storm.\u00a0 If three of more weeks out and on your last spray and you are seeing some leaf spot develop, applying a pint of chlorothalonil tank-mixed with 7.2 fl oz of\u00a0 tebuconazole or 5.5 fl oz of Alto or 5 fl oz of Topsin or 2.5 fl oz of Domark.\u00a0 If time for your last spray and very little leaf spot is present, then 1.5 pints of chlorothalonil may be all you need.<\/p>\n If white mold is popping up in your field late in the season and is confined to individual plants scattered across the field, then you may want to mix tebuconazole with your last leaf spot spray.\u00a0 If the disease is more severe, or you are really worried about it, then you might consider using 16\u00a0 fl oz or Convoy rather than tebuconazole.<\/p>\n It is generally advisable to wait to dig the peanuts until they are \u201cready\u201d based upon the hull-scrape test.\u00a0 This is true even if there is significant tomato spotted wilt in the field or some white mold.\u00a0 HOWEVER:\u00a0 if there is significant defoliation from leaf spot or significant white mold in the field, it often best to dig the peanuts earlier than planned to avoid excessive digging losses.<\/p>\n Cotton:<\/strong>\u00a0We have three diseases of significant importance in the field right now.\u00a0 \u00a0 Boll rot.<\/strong>\u00a0 The rain and heavy vegetative growth we have seen this year has created perfect conditions for fungal boll rot.\u00a0 We are seeing a lot of it.\u00a0 We are not seeing a lot of bacterial boll rot, though some is certainly there.\u00a0 Fungal boll rot is most severe in lower bolls deep in the canopy or where insect damage also occurs.\u00a0 Fungicides are not an effective treatment; only opening the canopy up to increase airflow and reduce humidity can help reduce boll rot.\u00a0 2.<\/strong>\u00a0 Areolate Mildew.<\/strong>\u00a0 I know that there is great concern and I have heard growers complaining that there fungicide applications did not stop the disease.\u00a0 Here are some thoughts.\u00a0 For the second year in a row, Areolate mildew is early and widespread.\u00a0 Areolate mildew can cause significant premature defoliation.\u00a0 I do know that fungicides like Headline and Quadris and certainly Priaxor can slow the spread of the disease, though not necessarily stop it, especially when it is well established in a field.\u00a0 It is not clear how much yield is at risk or that can be protected; but it is believed that significant premature defoliation is not a good thing, unless one is trying to open the canopy up to slow boll rot.\u00a0 Here are my recommendations, though they have not been proven with any hard data.\u00a0 If a grower is within 4 weeks of defoliating the crop anyway, save the money and don\u2019t spray.\u00a0 If the grower is more than 4 weeks of defoliating and the areolate mildew is not too severe (i.e. already causing significant leaf drop) then there may be a benefit to treating with a fungicide.\u00a0 This may not stop the disease but will slow its development.\u00a0 3.\u00a0 Target Spot.<\/strong>\u00a0 Target spot has been severe and widespread in this rainy season.\u00a0 I believe well-timed fungicides have been helpful this year.\u00a0 I don\u2019t believe there is any benefit to a fungicide application after the 6th<\/sup> week of bloom.\u00a0 Either there is too much disease already to stop it or there is not enough time for disease to develop.\u00a0 In this season, a second fungicide application 2-3 weeks after the first application is something to consider.<\/p>\n Late-planted corn:<\/strong> Southern corn rust is now commonly observed on older corn across the Coastal Plain, corn that is too late for it to matter.\u00a0 However, southern corn rust does pose a threat to younger corn and preventative protection with a fungicide is something to consider, especially as the crop approaches the tassel growth stage.\u00a0 Also, I am receiving numerous reports of young corn affected by northern corn leaf spot<\/strong> (Bipolaris zeicola<\/em>) which produces numerous, small-to-medium sized red\/brown spots, sometimes with appearance of concentric rings.\u00a0 Typically, corn is most severely affected by northern corn leaf spot early in the season and then grows out of it; however I cannot be sure that this will always be the case.\u00a0 I have no data on fungicides for management of northern corn leaf spot, but as it is closely related to northern and southern corn leaf blights, I am confident that mixed mode of action products we already use will be helpful for the \u201cspot\u201d disease.\u00a0 If a grower does spray, applications as early as V6-V8 would be appropriate. But again, I just don\u2019t know if it matters.<\/p>\n Soybeans:<\/strong> Asian soybean rust is still lightly scattered from Decatur County to Appling County, but has only been found so far in KUDZU.\u00a0 Soybean rust is certainly not a major problem at the moment; however it could become so.\u00a0 Management options are to protect the crop with a fungicide sometime between the R1 (early bloom) and R3 (early pod set) stages.\u00a0 Such timings may correspond well with other disease and insect control measures.\u00a0 Some \u201cCercospora leaf blight<\/strong>\u201d is being reported; this disease causes much of the upper foliage to take on a \u201cbronzed\u201d cast and then leaves drop prematurely leaving the \u201cbony\u201d petioles like skeleton fingers to the sky.\u00a0 Cercospora leaf blight also causes purple seed stain.\u00a0 Fungicide applications at pod set (R3) can help manage this disease.<\/p>\n","protected":false},"excerpt":{"rendered":" Row Crop Disease Update from UGA Plant Pathologist Bob Kemerait: PEANUTS: Getting lots of questions these days about late-season peanut disease problems.\u00a0 Just a few thoughts.\u00a0 \u00a0 Three weeks to go until you dig the peanuts and little-or-no disease in the field?\u00a0 I wouldn\u2019t put out any more fungicides unless there is threat of a […]<\/p>\n","protected":false},"author":38,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-403","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/site.extension.uga.edu\/cook\/wp-json\/wp\/v2\/posts\/403","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/site.extension.uga.edu\/cook\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/site.extension.uga.edu\/cook\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/site.extension.uga.edu\/cook\/wp-json\/wp\/v2\/users\/38"}],"replies":[{"embeddable":true,"href":"https:\/\/site.extension.uga.edu\/cook\/wp-json\/wp\/v2\/comments?post=403"}],"version-history":[{"count":1,"href":"https:\/\/site.extension.uga.edu\/cook\/wp-json\/wp\/v2\/posts\/403\/revisions"}],"predecessor-version":[{"id":404,"href":"https:\/\/site.extension.uga.edu\/cook\/wp-json\/wp\/v2\/posts\/403\/revisions\/404"}],"wp:attachment":[{"href":"https:\/\/site.extension.uga.edu\/cook\/wp-json\/wp\/v2\/media?parent=403"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/site.extension.uga.edu\/cook\/wp-json\/wp\/v2\/categories?post=403"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/site.extension.uga.edu\/cook\/wp-json\/wp\/v2\/tags?post=403"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}