(Continued from Pago A 1) control apple scab, cedar apple rust, and powdery mildew. Also, the root stock resistance to a com mon disease such as fire blight is being researched. The most common disease, according to Travis, is apple scab, which causes branches to turn brown and fall off. Through use of varieties, the researchers have seen some good control. “It can be a major problem if even one or two fungicide sprays are missed,” he said. "Even just one mistake can cause complete loss of the whole crop.” There are 11 different apple tree varieties in one test plot, of which nine are disease-resistant, accord ing to Tom Clark, research aid. Department of Horticulture. The tree root stock is carefully exa mined in combination with variet Insect infestation, particularly of the lesser peach tree borer, can be a problem for peach growers. The research department has been Investigating the numbers of Infesta tion with special pheromone traps that measure the amount of the males of the borer In the area, according to Ed Rajotte, associate professor of entomology; research at Penn State. Here, Jim Travis inspects a special slender*? Indie free-standi trelllsir lem. One of the ways that growers can reduce the current levels of fungicides and get control Is through the use of planting disease-resistant varieties, according to Jim Travis, associate professor of plant pathology, In the panama hat. There are several under research, which control apple scab, cedar apple rust, and powdery mildew. Also, the root stock resistance to a common disease such as fire blight is being researched. " Fruit Tree Research At Ag Progress Looks At IPM ies to discover which are the best at disease resistance. Also, root stock and variety combinations and resistance to insects and whether or not cer tain combinations draw certain amounts and types of insects—are under test at the research farm, according to Rajotte. Several varieties of peach trees are under test for their resistance to cytospora canker, which is a fun gus that attacks the dead wood. The disease, if unchecked, travels to the trunk, and can destroy the tree. Pruning and overall care is important to control certain peach tree diseases that attack the fruit, particularly brown rot. Removal of the “mummies,’* or decomposing and dead fruit completely away from the tree, is vital. Prop' " “«sential. T r There are 11 different apple tree varieties in one test plot, of which nine are resistant, according to Tom Clark, research aid, Department of Horticulture, looks at a hedgerow trellis system In use. vis and Clark emphasized the importance of keeping the tree open to air and sunlight, and keep ing the area at the foot of the tree clean and free of rotted fruit and dead branches. “One of the most important things you can do to eliminate brown rot is take all the peaches out of the tree —lake them out and get rid of them,” said Travis. He told the growers to make sure there are no peaches remaining on the ground or in the tree. Pruning should be when bud break occurs, because if the tree is pruned before that time, the canker fungus can take hold. Clark said that peaches must be thinned when the fruit size is small, about A inch. They should be thinned to 8-10 inches apart. By keeping them thinned, fruit size can be increased significantly, according to Clark. Also, insect infestation, particu larly of the lesser peach tree borer, can be a problem for peach grow ers. The research department has been investigating the numbers of infestation with special phero mone traps that measure the amount'of the males of the borer in the area. “If you have more information about when things are coming into the orchard, you can be more effi cient about any pesticides you may have to use,” said Rajotte. “Do some thinking about managing your pests before you apply a chemical spray.” Overall, it is important to get the exact information about the weath er at the right limes by carefully monitoring the weather at the exact site to determine what kind of pest controls to use. That’s why gather ing weather and environmental data is important, according to the researchers. Several on-site environmental . . such as the Austrlan-bullt KMSP system (which measures temperature, relative humidity, leaf wetness, and rainfall at each site), help predict the likelihood of possible disease or pest prob lems with crops. How the machines compare (some costing from $i,700-$2,000) and how accurately they measure is part of the research being undertaken by doctorate student Dave Truxell. monitors, such as the Austrian- a better source of weather data built KMSP system (which mea- that’s easy for someone to use and sures temperature, relative humid- is also very convenient and that ity, leaf wetness, and rainfall at will help them in their decision each site), help predict the likeli- making,” said Truxell. hood of possible disease or pest But for many growers, knowing problems with crops. How the how much pesticide to use. when, machines compare (some costing and if at all is a balancing act. from $1,700-$2,000) and how “It’s easy to reduce pesticide accurately they measure is part of use, but often, if you don’t do it the research being undertaken by wisely, then you’ll end up with lots doctorate student Dave Truxell. of problems with diseases and “What we’re trying to do it find insects,” said Travis. jm an. spotted tentiform leafmlner at the test site. Leaves bear the signature of the miner, “an Insect that makes a ‘mine* in the leaf," said Ed Ra]otte, associate professor of entomology at Penn State. A small moth lays eggs on the apple leaf, and a caterpillar emerges. The caterpillar is so small, said Rajotte, that it’s able to go “in between the upper and lower layers of the leaf and makes a little tunnel Inside the leaf." dlsease- Here, he
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