April 5th Pest Alert

April

April 5, 2022

Spring has sprung! Along with a little snow, we need the moisture, it just reminds us that weather is variable this time of year. You should be pruning now. Don’t prune spring flowering bushes such as forsythia & lilacs until they finish blooming. Remember to prune out no more than ¼ to ⅓ of the tree. Now is a good time to divide summer & fall blooming perennials. IF voles are causing the trails in your lawn from our long snow cover, trapping with a peanut butter/oatmeal mixture is very effective. 

If you had problems with mites, aphids, scale, or leaf rollers last year, you might want to consider applying an insect-preventative horticultural oil spray soon, as tree and shrub buds begin to swell and show the first green color (see attachment for pictures). Research indicates that oils are most effective (especially on scale and leaf-curling aphids) if you wait until the very first tips of green leaves begin to emerge before you apply oil. Oils smother newly hatching insects and insect eggs that are just about to hatch. Oils are less effective on insect eggs that are not yet ready to hatch.

Most spray oils are petroleum or mineral based, but vegetable oils are also available.  Oils can burn tender new leaf tissue, so apply them carefully. Lighter, lower concentration oil sprays are less likely to burn leaves. Use oils when temperatures are above 40 F, but below 80 F. Oils should dry completely before they are exposed to freezing temperatures. Apply oils several hours before night temperatures drop.

If you had disease problems last year, you could also apply disease-preventative sprays to trees and shrubs now. Check cherry, plum, and apricot trees now for oozing and cracking.  These particular species are more susceptible to bacterial and fungal canker diseases. Copper is the best disease preventative spray if you have bark cracking or oozing on cherries, plums, or apricots. If bacterial diseases, such as Fireblight, were a problem last year, the least-toxic disease preventative spray is copper or Bordeaux mix.  If fungal diseases caused spots on leaves last year, Copper or Lime sulfur is the least-toxic disease-preventative option. If you can avoid it, don’t mix oil sprays with lime sulfur or copper-containing sprays, especially if the weather is humid and temperatures are greater than 65 F. These sprays can burn sensitive new leaves and emerging buds, especially when sprayed in combination. Injured leaves and buds may turn yellow and drop prematurely. If peach leaf curl was bad last year spray ASAP with copper before BUD SWELL.

Soil temperatures are averaging 40F, so it’s time to aerate lawns and apply lawn fertilizers, and too early for weed and feed as a lot of the weeds are not actively growing yet.

A few perennial weeds are starting to grow now. Quackgrass and knapweed new buds are showing green. This is the best time to hit these tough weeds with least-toxic options which are usually not as effective on them. Several acid/oil weed-killing formulations can be sprayed on a warm, dry sunny day when temperatures are 55 to 65 F.

Moss seems to be a problem in many yards this spring. Soil compaction is one of the main reasons along with shade and daily watering practices. The best way to control moss is to aerate your lawn and fertilize with a moss killing formulation or a finished compost applied ½-1” deep.

It’s time to test garden soil and decide what soil amendments are needed.