Borer Spray Time

For those of you that live in the South, now is the time to spray
ALL stone fruit trees for borers. I normally use Triazicide for borers, but
I was out, so I used Malathion. This is the first year that I had
virtually 100% clean fruit from every tree in my orchid. I used
Malathion only twice all season, and it is now the only insecticide
I’ll use.


How did the peach trees do that you didn’t spray?

Malathion has a very short window of activity- 2 sprays won’t work at places with typical insect pressure in my neck of the woods except at those sites and years when pressure is extremely low. Sometimes peaches don’t even need spray because the fuzz is a repellent. The more suburban and less wild a neighborhood the less insect pressure there tends to be. I’ve eaten perfect cherries from an unsprayed tree in a Manhattan courtyard.

I’m confused.

  1. What borers affect fruit?
  2. Isn’t Triazicide ineffective above 85ºF?

I have to spray ALL of my trees. Since I have a suburban farm with
everything highly concentrated, it’s like a smorgasbord for insects.
Being that malathion is such a powerful contact insecticide, it kills
everything. But I have to be very precise and the sprays have to be
timed as perfectly as possibly, in order to not kill the pollinators.
Combining the spray program with a complete daily orchard hygiene
program, I get the results I want. May not work for you, since you
manage so many different sites.
Since I don’t like to spray, I try to get as much bang as I can. I do
have one consolation, since I don’t have to spray my pears, and I’ve
eliminated most of my apples.

Borers attack the tree itself, not the fruit.

What type of borers are you talking about? Peach tree borer or ambrosia borers? I lost 3 trees this year to in my guess borers. Had small pin head size holes on the trunk with saw dust. So I want to stay on top of this. I don’t have any fruit this year so I don’t mind doing something like sevin.

Susu it sounds like you had ambrosia beetles, Ray means peach borers.

The further south you are the later you need to spray for them (they come out based on # months to fall frost), I was dealing with them in late May. I paint raw neem on the bottom few inches of trunk and since I started that a few years ago I have had few problems. I found a few borers on new volunteer seedlings this spring but everything else was clean.

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Hope to get my peaches picked this weekend so I can spray the borers next week.

Lorsban works great for this purpose and I have enough for one more trunk drench.

It’s powerful stuff and everyone stays out of the orchard for 7 days after the spray.

Looks like I need to use another product next year.

How does Malathion work on the PTB? Do you just spray the trunk and lower scaffolds?

Works as good as any other insecticide. Don’t forget to drench the soil too.

When you drench the soil, how far out from the trunk do you go?

About 1 ft.

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Here the problem is always just at the base of the tree. I often wonder why you aren’t supposed to spray Lorsban on the base of trees when they have peaches. You only have to use a small hand sprayer and can precisely target the base of the tree on a windless part of a day. Where is the danger in this? Tiny amount of poison far from the fruit.

Lorsban is the only material said to reliably control ptb with a single app a year.

When I began my business of a fruit tree nursery and managing orchards I sought information about the best insecticides to use to control fruit tree pests, not just for me but materials that would work for home growers. Malathion was never widely recommended at the time, at least not in info sources that I was familiar with, because it just isn’t effective for a long enough period. Searching now I see that many cooperative extensions recommend it but some still suggest that it is inadequate. Here is a PSU description of its duration.

“Malathion is the most widely used home-planting insecticide because of its broad range of activities and safety for mammals. It is effective, however, for only 2 to 3 days”.

It kills what’s on the trees but doesn’t continue killing for very long, so I assume it would require many more sprays than other materials to accomplish adequate control in high pressure situations- that is when pests keep arriving and landing on your trees.

I wish I could find a chart that shows the comparative length of efficacy of common pesticides- maybe Olpea will sound in here- he usually has such research at his finger tips. My recollection is that Malathion lasts about half as long as Sevin and Sevin half as long as Imidan. I believe that pyrethroids generally last at least a long as Imidan.

However, labels on pesticides for home use don’t always allow for adequate amounts of active ingredient to get enough protection, judging from what I’ve read over the years of the experience of home growers on this forum and others. This may alter what is best for a non-commercial sprayer to use.

In the end, you have to go by what works for you in your orchard, but don’t assume someone else’s advice will apply to your conditions. Even in the same region, pest pressure at any given site varies widely, in my experience. Factors probably include the closeness of native woods (where many pest species reside). Hedgerows provide similar habitat for pests as do seldom mowed lawns and meadows. Even frequently mowed lawns with a lot of broad leaf weeds in the mix seem to have more pest pressure than grasses only. In other words, if your landscape and nearby land provides a lot of habitat for a wide range of fruit pest species, pressure will likely be higher. Insect pressure also varies highly season to season at any given site.

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I guess I’m losing my edge. I couldn’t find it this time at my fingertips, but that’s pretty close to what I remember. Assuming no rain, malathion lasts about 3 days, carbaryl about a week and imidan about 2 weeks. The formulation Sevin XR is supposed to last a little longer than regular carbaryl, but I don’t know how long.


How does Imidacloprid fit in here? If the fruit has been harvested already?

Isn’t it strange that if you search, most extension guidelines recommend various insecticides without any mention of this. It is as though the concern is only about safety and not efficacy. Whether the homeowner actually gets a crop does not seem of paramount importance, which is completely different than guidelines for commercial growers. Where plum curculio is a problem commercial growers keep active poison on fruit for the duration of pressure from that pest because damage can come too quick to rely on monitoring. For a home orchardist, there are usually many distractions to keep them from a daily search for arriving pests anyway.

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You would think a fully systemic insecticide like imidacloprid would be highly effective against peach tree borer, but it may not be.

This home orchard article says it’s not very effective.

The commercial version of imdacloprid for fruit trees, Admire Pro, doesn’t list peach tree borer on the label.

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