MAY TREE CARE 2009

Spring has sprung, at least my fruit trees are blooming. The codling moths are returning. May is the time to thin fruit, monitor and spray for pests, plant sales, and planting the summer garden.

Codling moths. This year, we will beat the codling moth. With the help of newsletter volunteers and probably Cooperative Extension, we will keep you updated on the biofix and the appropriate spray date(s).

For complete info on codling moth CTRL+ click http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7412.html. You can click on their degree day calculator link and time your spray using last Friday as the biofix date.

Also take a look at their discussion and link on ‘Bagging Fruit’. I did bag several hundred apple in past year with mixed results; some of the apples already had codling moth eggs laid and/or hatched when I put on the bags-hence the spray at blossom drop this year. The easiest bags to affix were the cheap ‘zip lock’ sandwich bags.

Thinning is an important step in producing larger, tastier fruit and will also help prevent damage from insects. Cherry trees do not need to be thinned; apples, pears, apricots, plums, peaches, and nectarines will benefit from thinning. Fruit should be thinned when the fruit is ¼ to ½ inch in diameter; after the fruit is an inch in diameter, it is too late to improve fruit quality by thinning. To thin, first lightly run your fingers over the fruit; a good number of the fruits will fall off as some fruits were not completely fertilized or the tree is selectively pruning itself. Then, remove any damaged/deformed fruits. Note that apples and pears form on clusters with the center fruit larger than the rest; those are the ones I leave on the tree. This year, I’m thinning apples and pears to 12” apart per limb; peaches and nectarines 8” apart and plums and apricots 6” apart. The object is to leave as much fruit as possible, but remove enough so that the remaining fruits will not touch when mature (insect larvae tend to bore into fruit where they touch).

Pests and disease seen in May include aphids, powdery mildew, and the first codling moth hatch. Look at the growth tips of the limbs for the dull gray coating that is powdery mildew. Generally, only one or two limbs will have it on new growth. Prune off the infected portion back to a branch or bud, dispose of the affected sprouts, and spray a disinfectant (like Lysol) on your pruning tools afterward.

Aphid damage will also occur on new growth and will appear as curled, deformed leaves especially on peaches, nectarines, and cherries. If only one or two places are infected, just squash the little bugs. If the whole tree is infected, attach a spray nozzle to your hose and spray water into the affected limbs from all sides. Aphids do not like humidity and the force of the spray will knock the aphids off and onto the ground. Being fat boys (actually all females) with skinny legs, the aphids will not be able to get back into the tree. Spray the tree daily, if possible in the morning, as the aphids knocked off the tree will slowly cook in the noonday sun.