Thursday, March 5, 2009
Dormant Oil Spray
If you have had problems with aphids or scale the prior year, you may want to apply a dormant oil spray to fruit trees. Now is the time to apply it for apple trees and pear trees. Pick a day when the sun is out and the weather is warm so all the eggs and overwintering adults you are trying to kill will be respirating at maximum potential. They smother better that way. If you are growing nectarines, which are already blooming by now, you have to apply in early January before they flower and include lime sulphur and a copper containing Bordeaux to kill the inevitable fungus that attacks them, Taphrina deformans (peach leaf curl). But you have to spray anywhere the rain can splash a fungal spore onto the tree, too. Some people put paper down under the tree to keep spores for splashing out of the dirt. It's a mess and it never worked completely even though I was meticulous about it. I gave up on nectarines. The fruit is too attractive to all the animals and fighting the fungus got old. Besides that, we could never figure out what to do with them besides pies, canning and eating out of hand. In addition, the fruit is a mess to deal with compared with anything else. The tree was very agressive and grew too fast, second only to the kiwi in growth rate so that was not a plus. In the end, it made good wood for the smoker. It was an education for a few years. Ours grew true from a discarded seed.
Apples, of course, won't breed true to the parent from seed. That's why the apple represented democracy and the people in colonial America to the early colonists (E Pluribus Unum, from many one). Each seed was unique in quality although still an apple variety of some sort. To become a "millionaire" in the colonies was to find a good tasting apple from a random seed that everyone would want to have for themselves(from many one). Because the seeds won't run true, everyone would have to take a twig (scion) from your tree to propagate (graft onto their tree) themselves. Colonists could charge what the market would pay for a good apple or scion and make their fortune. The Northwest territory was settled using apple tree plantings and this is where Johnny got his fame peddling apple seed and scions to the settlers along the Ohio River so they could provide proof of occupation and working of land claims by having an apple orchard of a size regulated by the government. Apples were the only way to make alcohol for yourself and a good way to add value to your crop. George Washinton did it every year at Mount Vernon. But I digress...(See: The Botany of Desire by Michael Pollen)
Comice and Asian pear trees. Today is the day the first flowers appeared. I usually time the dormant spray to this. However, having had no problems last year I will not apply it. The spray also kills the overwintering stages of beneficial insects and mites. I like to keep any beneficial organism be it nematode, fungus, collembola, insect, mite, bird, mammal, etc., around as much as is possible. They make a huge difference in the amount of work you have to do to control pests.
Rain total for last four days: 1.5 inches.
Total for the season is 17 inches.