Even though the groundhog saw his shadow this week and a major snowstorm is bearing down on the east coast, you need to start planning for spring chores, particularly when it comes to the fruit trees.

Dormant Oil Sprays

A horticultural spray, often referred to as a dormant oil spray because you apply it when the tree is dormant, is an important aspect of fruit tree care. It smothers the eggs and larvae of number of fruit tree pests, particularly scale and the eggs of red spider mites and aphids. Killing them now saves your fruit later.

There are several options when deciding which horticultural oil to use. Traditionally, the residual sprays are highly refined petroleum based oils that are applied with a hand-sprayer. Organic alternatives, such as cottonseed or a soybean based oil, are becoming more popular with orchardists who wish to steer clear of petroleum-based products.

When to Spray Fruit Trees

Whatever solution you choose, timing is critical. If you spray too early you might not kill insects that are still dormant (although youre smothering eggs). If you wait too long, you risk damaging new growth. Most of the time, you apply horticultural oils when the temperature is going to stay at 40+ degrees for at least 24-hours, but cooler than 70 degrees.

Since that can be a tough order in cooler regions of the country for instance, in some regions of Montana our nighttime temperatures during the summer barely reach above 40 degrees let alone in early spring wait until the tree buds are swelling, but havent burst. In my area, I’ll shoot for March. Itll be earlier in other parts of the country; keep an eye on your trees so you dont miss this opportunity.

Read the label of whatever spray you choose carefully, and follow the directions. Preferably pick a day that is cloudy, with little or no wind, and with no chance of rain for at least 24 hours. I realize this can be tough during the springs volatile mood swings, but choosing the right conditions improves your success. If it rains overnight, youll want to spray again at the first opportunity.

The oil only works if it touches the insects, so be sure to spray the tree thoroughly making sure you reach any crevices where insects might hide.

Lime Sulfur Spray

Lime sulfur is a fungicide that some gardeners also use as a dormant spray because it effectively kills the little sap suckers that are detrimental to fruit production and tree health, as well as working on powdery mildew, leaf spot and some blights. When you use lime sulfur spray in your fruit tree regimen, space the applications at least two weeks between the lime sulfur and other horticultural spray.

Also, while most dormant sprays are useful for most fruit trees, as well as some ornamental varieties, please note that the lime sulfur spray is toxic to pear trees so should be avoided. Opt for a copper spray instead.

If pests are a significant problem in your area, plan on applying a second round of spraying in the fall after the leaves have fallen, but for many people dormant oil spraying or using lime sulfur are part of the typical spring time orchard care