Xtremehorticulture

Wormy Apples a Problem with Honeycrisp Apples

Q. I have had wormy apples in our ‘Honey Crisp’ apple tree. Last year we had the same problem. I was told to spray a fungicide. I also sprayed Neem oil. I waited until the apples started to form. I still have these worms in every apple on my tree. HELP!!!  This is codling moth stuck on the sticky side of a pheremone trap. It is about 3/8 inch long and a true moth. Since the adult is a moth, the juvenile or immature form is a “worm” or larva. When populations are large they produce “wormy apples”.  A. I am guessing that you are dealing with codling moth. This is a common pest of apples and pears. They appear as “wormy apples”. They are creamy white and about 3/8 inch long when they are mature. Usually, they have a brown head. They start getting into the fruit when the fruit is small and may continue to feed as the fruit gets larger. You can read more about codling moth control by searching for “codling moth” and “IPM”.  https://ipm.ucanr.edu/PMG/PESTNOTES/pn7412.html The most reliable site is from the University of California. If this is codling moth, then picking and get rid of small fruit which is infested is the first step.  When the codling moth is flying, the moth will “sting” a small fruit causing it to drop. If it happens when the fruit is larger, it may stay on the tree. Look up for “stung” fruit or look at the ground for fallen fruit. Fruit produced later will have a larger percentage of stung fruit. Look for fruit tree species that are produced and harvested early.  Otherwise, their population continues to increase as the apple stays on the tree longer. Apples that stay on the tree longest are the most heavily infested. On the flip side, apples harvested early are the least infested. Populations of this pest increase with each generation produced. In our climate, expect codling moth to have three or four generations each year so start getting rid of infested fruit when the fruit is small. With each generation the numbers of these moths will increase and increase as the year progresses.  Start picking and getting rid of infested fruit starting about six weeks after it flowers. You can recognize infested fruit because of the brown frass coming out of it. The places where frass coming from the fruit are called “stings”. Stings are egg-laying sites by the female moth. Fruit that has frass coming from it will either fall from the tree or stay on the tree and get “wormier”. When you remove this fruit early, the population of “worms” has a better chance of staying low.  As fruit gets older, the “worms” get bigger and tunnel into the fruit deeper. They might feed on the seeds of these fruit before they pupate into a moth.  I have had good luck spraying either Bt or Spinosad several times over one season. Follow label directions. I have also had good luck if I use pheromone traps and get rid of them using these traps. I use one trap for every three or four trees.  This codling moth has already exited. Notice the “frass” left behind when it exited. Usually, pheremone traps are used for timing the application of sprays but when populations are low, I have had good luck “trapping them out”. Those traps should be put in the trees when the trees begin flowering or at least a couple weeks after they start to flower. Pheremone traps for codling moth can be bought from several places online. Look for them. The pheromone must be replaced regularly as per the instructions. Those wormy apples you got probably came from a neighbor who did not control them. This is a winged trap. More popular are the three sided “delta traps”. The winged traps, in my opinion, are better for repelling the moths. That is, better for using pheremones to keep fruit free of “worms”. The pheromones have better air circulation in those kinds of traps, the pheremones must be changed out more regularly, and the traps more concentrated. The delta traps are best for monitoring moths and telling you when to spray pesticides.

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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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July todo: change out the pheremone traps and pheremones

Pheremone sticky trap (sticky part is removable on the bottom) with an orange rubber thing that is impregnated with the synthetic pheremone. These must be changed regularly. Change pheremone sticky traps and replace the pheromones. Are you plagued by wormy apples, wormy pears, wormy peaches or nectarines, or wormy apricots? You may have codling moth in appes and pears and peach twig borer in your stone fruits.         Pheremone traps are sticky traps that attract specific problem insects through releasing of sex hormones produced in a laboratory to mimic the opposite sex and then trapping them with a sticky surface that can be replaced.         To control these insects you will most likely need to spray pesticide. Don’t be too alarmed because the pesticides you can use are listed for organic production. The most common ones used include Bt (Bacillus thuriengensis; aka Dipel or Thuricide).         The other chemical you can use is Spinosad. Spinosad is rougher on beneficial insects that Bt. You would spray just a couple of days when you get LOTS of these insects (the adults of these insects are small moths about 1/2 inch long. The larva or immature is the worm that gets into the fruit.

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