Fungus causes leaves to curl

I have been using Lily-Miller dormant spray for peach leaf curl on my nectarines; three times during the winter and the spring. It really hasn’t been too effective. I am going to put on the last dormant spray in a day or so. Should I use something that has oil in it? When the buds show a little pink, I then spray with another spray for insects. Can you suggest something that works for peach leaf curl?

Art Moore, Coeur d’Alene

Peach leaf curl is a fungal disease that grows between the cells in new leaves of peach and nectarines. It causes the cells to grow more rapidly than normal, which distorts the leaf. The disease spreads by spores carried by wind and rain to bark cervices and tiny spaces on buds. After overwintering in these spaces, the spores germinate as the leaf buds unfurl. You need to be using a fungicide registered for peach leaf curl. There are dormant sprays that also have a fungicide in them, or you can buy just a fungicide. This needs to be applied before the leaves break bud, so do it soon. Spray the tree again in the fall after leaf fall. Two properly timed sprays should be sufficient.

Prevent worms in gooseberry

I have a gooseberry bush. I’m wondering when I should spray it and with what. Every year it gets worms in the fruit, and I like a gooseberry pie.

Marcy Carney, Spokane

Unfortunately there are no insecticides registered for home use on currant fruit fly (gooseberry maggot). So you will have to use cultural methods to try to slow the bug down. Currant fruit flies are a small yellowish fly about a third of an inch long. It lays its eggs on the gooseberry fruit, and the larva bores into the fruit. When it emerges from the fruit, it drops to the ground and overwinters in the litter and top two inches of the soil. This spring, spread plastic under the bush to catch this year’s crop of dropping larvae. Carefully remove it later in the summer and dispose of the residual in the trash. Look for darkened spots on the fruit where the larvae entered and remove that fruit. In the fall clean up all the leaves and debris under the bush and put them in the trash. Cultivate the soil several times over the winter to expose the overwintering bugs. Repeat for several years or pull the plant out and replant a new one in another area of the garden. Cover the new one with floating row cover in the spring to deny access to any flies remaining in the area. Don’t use this method on your infected plant.