A2frL*ncaster Farming, Saturday, March 11, 1995 Late Blight Disease Threat Under Gun At State Potato Growers Meeting (Continued from Pago Al) potatoes unmarketable. What makes an outbreak parti cularly dangerous is that it can eas ily be generated by next-door neighbors who grow tomatoes in gardens. Without constant and fre quent fungicide treatment, late blight attacks tomatoes and is spread by air to potato plants. The disease can originate in tomato or potato hosts and can strike either. Fry showed examples of the effects of late blight at the Cornell University research plots in Ithaca, N.Y. Of the plots shown, late blight was started Aug. 2 last year and by Aug. 19, much of the foliage was gone. “The disease can increase and spread dramati cally,” said Fry. TTic disease can progress from 1 percent of total coverage to total death in a span of 18-28 days. What is worse is that good growing conditions for potatoes also spell good conditions for the outbreak and spread of late blight The fungus was originally brought to the U.S. from central Mexico in the late 1830 s and early 1840 s, according to Fry. It was the primary cause of the Irish Potato Famine in 184 S. It can readily spread by air to neighbor fields. The mating type of the original fungus was Al, an “asexual” organism that cannot reproduce itself. It needs a living host in order to survive. But more virulent and longer-lasting mating types emerged through the years, such as the A 2 mating type. What concerns researchers, according to Fry, is the emergence of more deadly and longer-lasting types, the A-7 or A-8 strains, which can reproduce and may be extremely difficult to handle. The new types, isolated in 1992, are very aggressive, can infect toma toes and potatoes readily, and are resistant to commercial fungicides. In 1994, US-7 isolates were dis- DON'T THROW AWAY OF YOUR HAY. Losses occur when crops are stored-regardless of the storage method Those losses are real--colorless, odorless and mvisible - you can't see them, but they're there. The air trapped within stored feed begins the fermentation process -and fermentation continues until all the air is consumed. The less air within the stored feed, the less loss. Because bunker silos are not easily packed, losses in bunker silos range from 27% to 45%. If the feed is valued at $3O per ton, every 1000 tons stored in a bunker would suffer losses from $B,lOO to $13,500. Tower silo losses range from 3% to 8%, or $9OO to $2400 for every 1000 tons. Those losses occur for every 1000 tons--every time feed is stored, year after year Before investing in any storage method, consider the total cosfs-mcludmg fermentation loss. Compare the various methods of feed storage Contact the Crop Storage Institute for your free copy of" Methods of Crop Storage" and "Know the Facts." Dr. William E. Fry, Depart ment of Plant Pathology, Cor nell University, told about 150 potato growers that the new isolate could be more fit, more virulent, more aggres sive, survive longer, and resist most major fungicides in the long run. covered in New York, Virginia, Tennessee, South Carolina, and Florida, according to the research er. US-8 isolates have been discov ered in New York, Maine, Pen nsylvania, North Carolina, Georgi a, Florida, Michigan, Illinois, Ore gon. and Washington. Because of the subsequent soft rot because of blight infection, many potatoes were culled and dumped after harvest. These dumping sites can easily store mat ing types. Withthe new A-7 and A-8 mat ing types, reproduction is possible. As a result, * ‘oospores” are gener ated, which can “recombine” traits and make the fungus more durable. Oospores can survive on clothes, equipment, soil, and other places. They can even survive freezing. The two long-term problems UP TO 45% Crop Storage Institute 219 N. 4th St. P.0.80x 560 Lafayette, Indiana 46902-0560 Even Maine had problems with late blight because of the bad weather conditions last year, according to Leigh Mor row, extension crop special ist, University of Maine. with the mating types are the fact that they can mutate and that the oospores have “a good survival structure.” said Fry. “They can survive a lot of things.” Fry examined some trials with various types of fungicides. The important thing for growers to remember is that they must apply fungicides early and often. Apply ing a low dosage frequently rather than a high dosage infrequently works best in blight control, according to Fry. Also, growers need to commu nicate with each other about the spraying programs, so that both can work together to ensure the blight is under control. Potato growers need to keep an eye out what is happening around them if a neighbor is growing tomatoes, and the tomato plants aren’t being treated for late blight, the risk of outbreak in potatoles is intensified. “There is no silver bullet,” said Fry, “for dealing with late blight.’ ’ C.B. HOOBER & SON, INC IKRWtK HOOBER EQUIPMENT, INC Intercourse, PA iBHHiHHIIIHHHHHHIii Middletown, DE (717)768-8231 ■■ (302)378-9555. c Tfie Saving CPCace WE SHIP PARTS DAILY FEDERAL EXPRESS HOURS Ut Mon.-Fri. 7 AM-5 PM; Sat.: 7 AM Noon CALL lic it Could Be Hie Have It Terry Bourgoln, director of plant Industries, Maine Department of Agriculture, spoke about the importance of making sure the fungus does not overwinter In storage. Management will depend on a var iety of factors, especially weather. According to Fry, New York extension believes late blight will be a problem this year. Conditions need to be humid, warm, and wet for late blight to occur. If the season proves hot and dry, late blight shouldn’t be a fac tor, according to growers. Growers need to improve scout ing, weather monitoring, and more closely inspect the seed source for signs of blight. Work is being con ducted at several universities on coming up with blight-resistant cultivars, of which some work proves promising. At the Wednesday morning annual meeting of the cooperative, Roger Springer, general manager, told those present to “communi cate and ask a lot of questions. It’s a serious situation that we all need to come to grips with.” Even Maine had problems with Authorized UPS Station Dr. Donald Daum, Depart ment of Ag Engineering, Penn State, provided Infor mation on “getting the whole plant covered" with a spray program. late blight because of the bad weather conditions last year, according to Leigh Morrow, extension crop specialist. Univer sity of Maine. Particularly hard hit was the east and northeast portions of the state, in Aroostook County. Where areas had twice the rainfall, the problem was really serious, according to Morrow. The drier areas of the state were able to keep late blight under control. The total Maine potato cull crop was 500,000 CWT, and piles were covered and composted. What growers learned through the exper ience was the importance of con trolling the inoculum “and pro tecting foliage and that’s it,” said Morrow. He told the growers to check the seedlots and “test your seed. “I don’t think we can expect to go to zero tolerance on blight," he said. (Turn to Pago A2l) Via FED. EXP. - UPS - PPSH - BUS-AIR FREIGHT, ECT. rv Pick Up Phone And JvrJßl Place Your Vl JpPTI * 3 ® rts irTkgJL 1 1 Order With Us
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