Ask a Master Gardener: Pokeweed, plum invaders and a pest update

Q: What is this plant (see photo)? It is coming up in my berry patch. Is it poisonous? How can I safely control it?

A: This is a common weed called pokeweed (Phytolacca americana). It is spread by birds eating the berries, which are poisonous to people and certain mammals. The foliage is also poisonous, but can be handled without causing any skin rash or irritation. It is an herbaceous perennial with a significant taproot. It can be pulled up easily when smaller, but when large may be easier to control chemically. It is highly susceptible to glyphosate (Round-up). To avoid injuring the adjacent berry plants, cut the plant at about 6-12 inches above the ground and treat the freshly cut stem with glyphosate concentrate. Not all Round-up formulations are labeled for veggies and fruits, but the weed-grass-killer-super-concentrate is. Applying it as a concentrate to the fresh cut stem or trunk of a plant is described quite well on the label. Generic "glyphosate" products (that's the only active ingredient of this Round-up product) are available and should be labeled similarly, but, of course, always check the label.

Q: I have plums and there are these little white worms (about a 1/4 inch) inside the fruit, often right next to the pit. What caused this and can I do anything about them now?

A: That almost assuredly is plum curculio. It is one of the most difficult to control pests on plums and apples. It can also infest peaches and apricots, but its favorite is plums (hence the name). The adult is similar to a weevil and it comes out at night and lays eggs into the developing fruit. They can have two generations. It is typically the second generation larvae that is associated with ripening fruit. However, due to the late spring and your plums being fairly early, this might be the first generation. For apples they aren't as disgusting, as they cause a small bronze half-moon shape on the skin, and the relatively small area they damage can be cut out. Or just eaten, as they are white, the apple flesh is white and many do not even notice them.

One needs to spray with an insecticide to control the pest before the adults lay eggs into the fruit. The first application should be made just after flowering and three applications, possibly four, are needed spaced about every two weeks. All may not be lost. The infested fruit is damaged, thus it ripens faster, as the damage causes the release of a ripening hormone (ethylene). These fruit often fall off quicker and if some are left behind and when ripe, may not be infested.

Q: Something went through my garden and nipped off the developing green beans and flowers, but didn't eat the foliage. What animal most likely did this? Also, my motion detector light went off about 4 a.m.

A: Deer would be the most likely culprit, and any smaller animal (possum or rabbit) would have mussed up the plants to get at the green beans. Your motion detector light probably tells you when they visited. A good question is whether the light from it helped the deer to do such a nice job nipping the beans and flowers without messing up the plants.

Q: Some of the older leaves on my tomato plants are curling. Is this a problem?

A: The older leaves on tomatoes may curl due to heat and dry conditions. Maintaining adequate soil moisture will lessen it, but given the heat we are having, it may be a response to just that. Tomato varieties differ in heat tolerance, so you may see more of this with some than others. Sucker pruning of tomatoes, especially if many suckers are removed at once, can trigger leaf rolling on older leaves. Leaf rolling of these old leaves isn't hurting the plant.

Pest update: Japanese beetle numbers increased this past week, but are only at about a 1/10 of last year's summer peak. Another pest to be on the look out for are spider mites. Hot, dry weather aggravates their likelihood to be problematic.