2Applied Insecticide Toxicology Laboratory, Department of Entomology, Michigan State University, East Lansing, MI, USA.1Tree Fruit Pathology Laboratory, Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI, USA.Another factor that hinders the effectiveness of spraying is the tree canopy which covers blossoms that hang low, making them inaccessible to the spray.Srđan G. Hence interval spraying does not address all the blooms in an orchard. The bloom period on an apple tree is four days, but trees bloom at different times over a much broader period of time. We harness other natural pollinators in the orchard, who help us out by carrying BVT active ingredients from one bloom to another. An additional benefit is cross pollination. We use commercially-reared bees to accomplish this on a continual basis through their natural process of pollination, targeting each and every bloom in an orchard during the bloom period. The BVT system ensures each flower on an apple tree is delivered active ingredients to help combat this contagious disease. The primary cause of Erwinia is through honeybees and other insects, birds, rain and wind – all of which can transmit the bacterium to susceptible tissue in an apple tree. Mites are a very common pest and infest many crops and wild plants. Left unchecked, mite populations can affect fruit color and result in premature fruit drop. A characteristic brown foliage that, in severe cases, becomes bronze, results from heavy mite feeding. Mites feeding on leaves also reduce the ability of leaves to manufacture enough food for desirable sizing of fruit. Moderate to heavily infested trees produce fewer and less vigorous fruit buds. The most serious injury occurs in early summer when trees are producing fruit buds for the following season. Mites feeding on leaves cause injury to the tree by removing leaf tissue. Mites multiply rapidly in hot dry weather, but is slow under cool wet conditions. Young mites feed until mature and reproduce in newly opened leaves. Overwintering eggs in the bark hatch during the bud and bloom stages. The European red mite is a major tree fruit pest attacking apples, stone fruits and pears. Michigan State University Video: Early season build up of fire blight.Michigan State University Video: Fire Blight – Shoot Blight Development.Healthy trees can be infected by fire blight bacteria spreading from infected trees in the same orchard, or from other orchards or neglected trees in the region. Entire branches can be killed and the trees often appear burnt and blighted in a matter of a few weeks. Bacteria ooze from cankers and affected fruit. The bacteria continue to migrate into the twigs and branches where new cankers form. The bacteria enter apple trees primarily through the blossoms after which the shoot tips wilt and appear in the form of a shepherd’s crook. In spring the bacteria ooze from overwintered cankers in apple branches and are dispersed in the orchard by rain and insects. Fire blight is caused by the bacterial pathogen Erwinia amylovora which also attacks pear trees and related ornamental plants. Fire blight can rapidly spread and destroy many or all trees in apple orchards, especially when rainy and windy conditions are frequent during and after the blossoming period.
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