Xtremehorticulture

Using Pheromone Traps to Control Wormy Apples

Q. We have six apple and two pear trees in Ely, Nevada. This year all the fruit had worms in them. The damage started when the apples were only about 1 inch in diameter. Every single fruit had worms in them. I am suspecting a moth but I’m not sure. We sprayed with Neem Oil before they blossomed and after the fruit set. Any ideas? A. This “worm” is the juvenile or immature form of a moth called the codling moth. They ruin the apples or pears by devouring the inside of the fruit leaving their feces and allowing for the fruit to start rotting. Hence, “wormy apples” which can look disgusting later. In commercial apple and pear production, as many as eight “cover sprays” are applied to the trees every year to prevent wormy apples. An early sign your apples may be wormy. The codling moth lays an egg on the outside of immature apple or pear fruit. The warm hatches and tunnels inside the apple. Conventionally, insecticides are sprayed on the trees and fruit to kill the warm before it enters the fruit.             Codling moth is the most destructive insect of apples and pears in the world. We see codling moth damage to apples and pears in the Las Vegas area as well. But because we are in the Mojave Desert, this pest is not as damaging as it could be. As more homeowners plant more fruit trees however, we will see more of this pest creating damage to these fruits in the future. This is a winged sticky trap with a reddish brown rubber lure that was impregnated with a pheromone. This sex hormone is released into the air and one gender of the past is lured to the trap where it is stuck. When the sticky bottom of the trap is full or no longer sticky, it is replaced. In a dusty environment this can be weekly. The lure weakens over time and is replaced to keep the scent at its maximum filling the air.             As I mentioned in passing, one method of control is using insecticides as a “cover spray”. A cover spray is an insecticide sprayed over the entire tree, not just the fruit. Sprays are applied often enough to create a poisonous barrier for the female codling moth. Neem oil will not work in this way against this pest. This is a Delta trap used mostly for monitoring when the moth is flying. It does a great job telling you when sprays are needed. I like the trap better when relying only on disrupting the mating of insects for control.             If you choose to use an insecticide, it must be something other than Neem oil and it must be sprayed frequently over the entire tree. There are insecticides you can purchase from the store but the secret is to apply it often beginning when the fruit first begins to develop.             Another option, pheromone traps, can either reduce the number of times the tree is sprayed or even eliminate spraying altogether. Pheromone traps are cardboard traps which contain a sex hormone released into the open air. This pheromone prevents the male codling moth from finding a female and, instead, gets stuck in a sticky mess inside the trap.             Under some circumstances, these pheromone traps may catch enough males to prevent female moths from laying their eggs. This interruption in mating can prevent wormy apples from occurring.

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Apricot and Apple Tree Growing Poorly

Q. My apple and apricot trees have small leaves and not much new growth. The few dark green leaves are almost dead. I fertilized the plant in the prescribed periods and watered the plant as in previous years. The apple tree made flowers but few fruits. The apricot had lots of apricots and dropped some earlier but few green leaves. Apricot tree sparse and not filling in properly. Having a tree with the canopy this open can lead to borer problems if it doesn’t already have them. Apple tree is sparse. The same thing applies to Apple trees. They need enough water and a big enough basin to water the roots, nutrients which we supply through rich compost or fertilizers, and a surface mulch which decomposes to enrich the soil. A. Thanks for the pictures. I think the problems are a combination of water, fertilizer and soil. As you know, the trees should be thick and dense this time of year. They are not because, I think, they lack these three ingredients. Water Your trees are about 8 to 10 feet tall and would need about 20 to 30 gallons of water every other day during the hot summer months. As trees get older and larger, they need more water. That works out to about 75 to 100 gallons each week.             There is a basin at the bottom of the tree that is maybe 3 feet in diameter. Increase the size of that basin to about 6 feet in diameter or 3 feet from the trunk in all directions. That will accommodate more water and spread it about a foot beyond the basin. Compost or fertilizer             Spread about 1 cubic foot of good quality compost in the basin away from the trunk before you water it again. This compost should have a high nutrient content such as Viragrow’s. Many do not.             After rebuilding the basin in a six-foot diameter around the tree and applying compost, fill the basin with a hose or sprinkler on the end of a hose. Fill the basin twice. Mulch             Cover the soil in the basin with woodchips from local trees if you can find them. If you can’t find any, use straw 4 to 6 inches deep until you can find some woodchips.             Increase the amount of water to the tree by covering that soil with about one – two inches of water flooding the basin. Water the tree three – four times per week using this basin and flooding technique. You should see new growth starting in about 7 to 10 days.

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