Tuesday, March 20, 2007

Plum tree fruit in East Haddam, CT

Here's one I have been asking for 3 years without an answer: My green/yellow plum tree in East Haddam, CT. gets fruit every year but the plums fall off, every one, by the time the fruit is the size of a large olive. The dark red plums do very well.

Have you ever seen any insect damage in the fallen, premature fruit?
There is a little beetle called a Plum curculio (Conotrachelus nenuphar). In spring, the adult females lay their eggs in the developing fruit, creating distinctive crescent-shaped slits. The hatched grubs eat the fruit tissue and eventually they fall to the ground. The grubs then leave the fruit, burrow in the soil, and pupate into adults. The damage seems visible enough though that you would have noticed it over the last few years.

Another question, and more difficult to answer. Do you know the species of the tree?
The genus is Prunus, that we know. The reason I ask is because so many fungal diseases and pests are very host specific, and knowing the exact genus and species of the tree might help narrow down the list down some. Again, I apologize, not the easiest question to answer.

Otherwise I am sure you are familiar with the general needs of the tree. Plums require full sun, well drained soil, soil pH between 5.5 and 7, and a regular watering schedule. If the tree consistently drops premature fruit I also wonder if supplemental watering might help the plant hold on to its fruit through maturity. However, if you have another tree in a similar location that is doing fine, again, I am stumped.


  1. Upon doing some internet research we found that a Shiro plum, Prunus salicina 'Shiro', does require other Japanese plums to pollinate it. According to a number of internet businesses 'Redheart', 'Santa Rosa', and 'Methley' are ideal species to use for pollinating Shiro plums.

  2. The plot thickens as I find out that Jane already has a 'Santa Rosa' on her property in addition to the 'Shiro'. Now we are wondering about the length of the growing season and whether or not that is enough of a factor to force the fruit to drop prematurely.