I have a peach and a plum tree. Both are doing well, but the leaves are showing signs of being eaten by "something". I can find no actual pest, such as caterpillars or aphids, on the tree itself. The holes are small and plentiful in the leaves - lots of little bites. Today I found a ladybug on my peach tree - not sure if that's a sign of aphids? I have applied BTK once this year, since last year we found a couple of caterpillars. But the holes seems to persist, and i'm reluctant to keep applying when there is no actual evidence of caterpillars. (I live in the lower mainland.) Any help would be appreciated!
If you don't see any insects then your problem might be "shot-hole" blight (Coryneum blight). This can cause small holes in the leaves of fruit trees. I don't know much about how to treat and diagnose it but it might be worth looking into on line.I wouldn't be too quick to spray (even BT) for a couple of caterpillars; save it for a more serious infestation. A healthy tree can easily withstand some pest damage and without caterpillars there would be no butterflies. Caterpillars are also an important food source for birds especially when they are nesting.
Hi Denis/Teresa - After some research and comparison, i'm fairly sure it's not Coryneum blight. The holes around the edges are yellow, as opposed to red, and the fruit is perfect, without blemish. I'm holding off on the BTK spraying, as I really don't want to spray if i don't need to, but am still not able to identify my mysterious pest. All of my trees are young trees, however, so i do feel that i need to discover the pest before it destroys much more of my trees!
The most common reason today for holes in the leaves of many varieties of trees and shrubs in our area seem to be what has been referred to as "Abiotic Stress"(natural causes). The lack of ability for plants to maintain full foliage. No circular red rim around the hole like Shot Hole, no Frac or webbing from Span Worms folding the leaves, just plain old large clean holes usually running along and between the veins, getting larger as the season grows. Often you will see brown dots and tiny holes slowly developing and enlarging. Maples and Cherry's are notorious for this, but look around your garden and neighborhood for similar damage on various varieties of plants.