Archive for March, 2007
Fruit trees in the Hood River Valley are getting ready for spring. Currently they are in the growing stage called “bud swell,” which means just as it implies: the once dormant buds are swelling, and the light colored edges of the bud scales are becoming visible.
The tree’s leaves are still over a month away from showing. The orchard floor is fast becoming a lush and vivid carpet of new grass growth, and every now and again you’ll find crocus flowers emerging. Pear growers choose this time to spray an organic, horticultural dormant oil to protect against a number of pests, the main one being an insect called Pear Psylla (pronounced sill-uh). The psylla creates an undesirable black sooty mold on the tree’s fruit, leaves and bark, as well as dark patches of dead tissue on leaves. Heavy infestations can weaken fruit buds, reduce shoot growth and cause premature leaf drop. Dormant oil applied in early March will prevent the psylla from laying eggs on the pear trees for about 6 weeks until leaves emerge.
Horticultural oils like this are organic contact insecticides that work by suffocating the psylla eggs, larva, pupae, and adult insects. Other pesticides eliminate pests by interfering with biochemical processes; however this method is much safer than many pesticides.No comments