In late August 2014 a new aphid was found attacking grain sorghum in Georgia.\u00a0 This aphid is the sugarcane aphid (Melanaphis sacchari<\/em>). \u00a0\u00a0\u00a0Sugarcane aphid will be a serious pest of sorghum in 2015 with most fields being treated one or more times.\u00a0\u00a0 Infestations are developing throughout the state mostly in the coastal plain region now.\u00a0\u00a0 I expect the aphid to be throughout the state very soon in 2016.<\/p>\n Background:<\/strong>\u00a0 The sugarcane aphid (SCA) has occurred in Florida since 1977 and Louisiana since 1989 feeding on sugarcane. \u00a0About 2 years ago the aphid shifted hosts and a strain with a preference for grain and forage sorghums appeared. \u00a0First found in eastern Texas near Beaumont, this new strain has rapidly spread eastward across the southern United States in 2014.\u00a0 It is now widespread across the southern U.S. and occurs from Texas, Oklahoma and southern Kansas to central Florida, most of Georgia and as far east as southeastern Virginia.\u00a0 The aphid infests all types of sorghum including Johnsongrass, Sorghum halepense<\/em>.\u00a0 Indeed Johnsongrass supports populations in areas were grain sorghum is absent.\u00a0 The aphid must overwinter on green sorghum plants in areas where volunteer sorghum and Johnsongrass do not go completely dormant.<\/p>\n Photos: Xinzhi Ni, USDA-ARS, Tifton, GA and \u00a0Pat Porter, Texas A&M AgriLife Extension<\/p>\n Identification:<\/strong> It is important to scout sorghum fields in your area for its presence. \u00a0\u00a0It is fairly easy to identify.\u00a0 Wingless forms are a uniform pale cream to yellow with black feet and black cornicles (the small tubes present on the end of the abdomen).<\/p>\n Damage: <\/strong>Where it has been found in Georgia, it is present at very high numbers of several thousand aphids per plant across entire fields.\u00a0 Large populations of fluid sucking aphids cause serious injury to the plants including death of leaves and sometimes plants. Feeding injury causes reddish lesions on the stems and leaves.\u00a0 \u00a0Studies have showed that the greatest yield losses occurred during pre-boot, boot and early panicle emergence stages with yield losses of 52 \u2013 100%.\u00a0 Pre-boot infestations at this time can prevent heading and infestations during boot and early panicle emergence can cause sterile heads.\u00a0\u00a0 Infestations during soft dough also reduced yield by about 20%. The aphid can remain present in large numbers in the field until harvest.\u00a0 It produces large quantities of honeydew, a sticky sugary substance that adheres to the plants, which may interfere with harvest and could damage combine harvest equipment.<\/p>\n Management Practices for SCA Aphid<\/strong><\/p>\n 1) Plant early<\/strong> \u2013 Because the aphid migrates northward in the spring, early plantings may avoid may avoid very large infestations.\u00a0\u00a0 Late planted double-crop plantings are at greater risk of severe infestations. \u00a0\u00a0Some hybrids have been shown to have some partial tolerance to the aphid.\u00a0\u00a0 This table from LSU lists grain sorghum hybrids with some degree of tolerance to SCA. https:\/\/www.lsuagcenter.com\/NR\/rdonlyres\/EF5A0F6C-B46D-4C16-9E8F-C355F5B7DE90\/105488\/Pub3523SorghumHybrids_FINAL.pdf<\/a><\/p>\n 2) Use an insecticide seed treatment<\/strong>.\u00a0\u00a0 My trials last year found that insecticide seed treatment would limit seedling infestations for 30 \u2013 40 days after planting.\u00a0\u00a0 All registered neonicotinoid insecticides are effective including thiamethoxam (Cruiser), clothianidin (Poncho, NIpsIt Inside) and imidacloprid (Gaucho, others).\u00a0\u00a0 Most grain sorghum seed was treated with one of these seed treatments in 2016.<\/p>\n 3) Scout early and often<\/strong>.\u00a0\u00a0 Fields can quickly be inspected for the presence of aphids by looking are on the underside of leaves.\u00a0 Once aphids are detected, scout at least once, preferably 2 times per week, because aphid numbers build very quickly. \u00a0Shinny lower leaves with honeydew are a clear sign of infestation.<\/p>\n 4) Beneficial insects usually do not control infestations.<\/strong>\u00a0\u00a0 SCA and their honeydew attract large number of beneficial insect predators such as lady beetles, syrphid fly larvae and lacewings. \u00a0A parasitic wasp is present in and caused infested aphids to turn a dark blue-gray color.\u00a0 \u00a0\u00a0No aphid fungal disease has been observed either.\u00a0 Generally the rapid rate of increase in aphid populations overwhelms the beneficial insects and severe plant damage usually occurs.<\/p>\n 5) Treat when aphids reach threshold levels<\/strong>.\u00a0 The current threshold is 50 or more aphids per leaf on 25% pf plants<\/strong> preboot stage through dough stage.\u00a0 Once threshold is reach do not delay application because infestations can very quickly go from the threshold level to 100% infested plants and hundreds of aphids per leaf.<\/p>\n 6) Use an effective insecticide<\/strong>.\u00a0 PYRETHROID INSECTICIDES ARE NOT EFFECTIVE and may flare infestations by killing all the aphid predators. \u00a0Regardless of the insecticide, rapidly expanding populations are difficult to control. \u00a0Foliar insecticide options for SCA in Georgia are:<\/p>\n 7) Good coverage is key to effective control<\/strong>.\u00a0 Use tips and GPA for maximum coverage especially lower in the canopy. A minimum of 10 gpa by ground and 5 gpa by air is highly recommended.<\/p>\n 8)\u00a0 Avoid pyrethroid insecticides for other sorghum pests<\/strong>.\u00a0\u00a0 For sorghum midge try to avoid routine pyrethroid sprays for sorghum midge.\u00a0 Instead scout and treat at 1 adult per panicle. \u00a0Chlorpyrifos (1 pint per are) for low to moderate infestations. \u00a0\u00a0If pyrethroids are used they can be tank mixed with Sivanto (Do not use Transform during bloom). \u00a0\u00a0Early plantings often avoid serious midge infestations. \u00a0For fall armyworm in the whorl, the threshold is 50% infested whorls.\u00a0 Use Belt, Prevathon or Lannate which are specific to caterpillars.\u00a0 For headworms, corn earworms fall armyworm, sorghum webworm, the threshold is 1 worm per head and use Belt, Prevathon, Beseige or Lannate.<\/p>\n 9) Check fields 2-3 weeks before harvest for infestations<\/strong>.\u00a0\u00a0 A treatment may be needed if large numbers are in the head to prevent damage to combines. \u00a0Hybrids with taller stalks and more space between the grain and upper leaves may make harvest easier by reducing the amount of leaf material going through the combine.\u00a0 Large infestation producing large amounts of honeydew and sooty mold may interfere with harvest desiccants.\u00a0 Transform WG can be applied up to 14 days before harvest.<\/p>\n 10)\u00a0 Silage\/forage sorghum control.<\/strong>\u00a0 No work was done specifically on SCA control in silage\/forage sorghum last year, but I and Dennis Hancock have some trial out this year.\u00a0 So the same recommendations for grain sorghum also apply to silage and forage sorghum.\u00a0\u00a0 Both Sivanto prime and Transform can be used on silage and forage type sorghums.\u00a0\u00a0 Grazing \/ hay interval is 7 days for both products.\u00a0 In forage\/hay types, the later cutting were damaged last year.\u00a0 Spray coverage is difficult when plants get tall.\u00a0 If aphids are present but below threshold consider a spray application as late as possible before the crop gets too tall.<\/p>\n 11) Sweet sorghum.<\/strong>\u00a0 Sivanto prime, Transform and chlorpyrifos cannot<\/strong> be used on sweet sorghum.\u00a0 There are no effective treatment options for sweet sorghum.<\/p>\n Summary.<\/strong>\u00a0\u00a0 Most likely SCA will infest sorghum statewide in Georgia in 2016.\u00a0 SCA will be difficult to manage cost effectively.\u00a0\u00a0 Planning and scouting will be keys to successfully managing this new invasive pest and prevent serious losses to sorghum in Georgia in 2016.<\/p>\n For additional information and photos see:<\/p>\n https:\/\/www.lsuagcenter.com\/NR\/rdonlyres\/C6BA2774-31C5-41AF-8A30-9AC50CD1135A\/101354\/pub3369SugarcaneAphids2NDPROOF.pdf<\/a><\/p>\n https:\/\/www.mississippi-crops.com\/2015\/02\/24\/management-guidelines-for-sugarcane-aphids-in-ms-grain-sorghum-2015\/<\/a><\/p>\n https:\/\/news.utcrops.com\/2015\/03\/sorghum-thinking-sugarcane-aphid-control-2015\/<\/a><\/p>\n![\"sugarcane](\"https:\/\/site.extension.uga.edu\/colquittag\/files\/2016\/06\/sugarcane-aphid-pic-1.jpg\")
<\/a>![\"sugarcane](\"https:\/\/site.extension.uga.edu\/colquittag\/files\/2016\/06\/sugarcane-aphid-pic-2.jpg\")
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