Use Traps on Fruit Trees Not Insecticides

Q. I was reading your blog about peach tree bore and I am planning to buy some pheromone traps. Which traps and lowers should I buy?

A. In southern Nevada we do not have peach tree borer. We have borers that get into peach trees but these are not peach tree borers. They are thought to be the flat headed Apple Tree Borer and/or the Pacific flatheaded borer. To my knowledge neither have lures and no way of trapping them using pheromones.

Pheromone traps can be very effective at removing some pests that attack fruit trees or fruit but there are not pheromone traps for every pest. Pheromone traps are highly selective and very effective at luring a very specific pest to the trap where it is stuck to a very sticky surface. You must be 100% certain of the pest you are trying to lure or it will not work.

This is the sticky bottom of a winged trap. The reddish-brown upright capsule in the center is made of soft rubber impregnated with the sex attractant called a pheromone.

            In this case you mentioned peach tree borer. This is not the insect we are trying to attract. We do not have this pest in Southern Nevada so if you buy a trap for peach tree bore you are wasting your money.It is a problem in more northern climates such as Central Utah, Colorado and California.

            The pest we are interested in is the peach TWIG borer, not the peach tree borer. The peach twig borer attacks new growth in the spring, killing it, then later generations attack the soft fruit causing “wormy peaches”. Occasionally we find this “worm” in apricots, nectarines and almonds.

This is the kind of damage we see very early in the season by the peach twig borer in new growth of peach and nectarine. This insect builds its populations through the growing season until finally it will attack ripe fruit. It may also attack apricots and almonds.

Pheromones are chemicals released into the air by one sex of an insect to attract the other sex so that mating is a sure thing. Pheromone traps use a capsule laced in pheromones that mimic this sex attractant. This capsule is placed inside a very sticky trap. The insect of opposite sex flies to this trap expecting to find a mate but gets stuck instead.

This is peach twig borer "worm" or larva in mature peach just harvested from the tree. This is the insect that is responsible for "wormy peaches". The adult is a small moth.

Pheromone traps were designed primarily to inform farmers when these bad insects were flying so that an appropriate pesticide could be applied exactly at the right time. Otherwise farmers are left to guess when to make these applications.

Coddling moth damage to apples or "wormy apples".

Under some circumstances pheromone traps can be placed in fruit trees to trick the opposite sex and catch them before they mate. If the pheromone trap is very effective at catching these insects then no insecticide needs to be applied. This type of insect control is sometimes called “mating disruption” or “trapping out” the problem insect.

Here is a winged trap for peach twig more hanging in a peach tree with the pheromone capsule located on the sticky bottom.

Pheromones are made for many different types of insects that are problems for farmers but the two insects I usually place pheromone traps out for in southern Nevada include the peach twig borer and coddling moth for apples, pears and quince. These will vary depending on where you live.

I prefer winged traps over the so-called Delta traps. I seem to get a better catch with the trap that is open on all sides.

This is the Delta pheromone trap. I think it works fine for detecting when the insect is present but I do not like it as much as the winged trap for mating disruption. I think the winged trap works better for mating disruption because it is open on all sides.

Even though it said it's not supposed to work, I have been very lucky trapping out both of these insects with lures and traps rather than applying insecticide sprays. I put my traps inside the Orchard perimeter so they get some protection from wind. I flood the area with the pheromone scent from these lures and it appears that they are confused enough that few find their mates.

Coddling moth damage on pear in Afghanistan. Damage is the same but the timing is different.

I start put out a single trap of each in about April in Las Vegas because I don't want to miss the first flight. However, I usually don't start catching them until about May. Their appearance coincides with heating degree days over a certain baseline temperature. These heating degree days can vary depending upon the weather so emergence can be earlier or later in some years. It also varies with the climate in your area.

Peach twig borer in the outer husk of almond. It usually does not get in the nut or kernel but can.

As soon as I start catching moths in the traps I immediately deploy the rest of them flood the area with this pheromone. I change out the sticky bottom once every two weeks or so and the lures are changed out monthly. I don't listen to closely to recommendations because they are for monitoring and not for mating disruption. Because I don't have hundreds of trees I choose to spend a little bit more money on lures and traps rather than pesticides and applying sprays.

I use one trap for about 20 to 25 trees. I replace the bottoms every couple weeks when trapping because of dirt and moths getting stuck in the traps and making them less sticky.

Buy enough sticky bottoms and lures to last from April until you harvest. Keep the lures in sealed plastic bags in the refrigerator until you are ready to use them. Technically you are not supposed to put them in the same refrigerator as food. Sticky bottoms and traps last from year to year but lures should be purchased fresh every year.

If you want a class on how to do this let me know and I will put one together.