Prevent Blossom End Rot
Blossom end rot shows up as dark, sunken spots on the blossom end of tomatoes, peppers, and squash. It's caused by a calcium imbalance in the plant -- the soil may have adequate calcium, but the plant isn't able to take up enough to supply the rapidly developing fruit. To minimize the problem, keep soil evenly moist, apply a layer of mulch to conserve moisture, don't overfertilize (especially avoid high-nitrogen fertilizer), and avoid damaging plant roots while cultivating.
Dispose of Moldy Strawberries
If you have a strawberry bed, harvest frequently and remove any berries that show signs of grey mold or rot diseases. These berries not only are inedible, they quickly spread the diseases to other ripening fruits. Pick and remove the rotten berries and mulch under plants with straw to reduce contact with the ground where the disease spores reside.
Foil Japanese Beetles
Japanese beetles will soon be out in full force, feeding on roses, grapes, beans, and many other plants. Control them by handpicking early in the morning or in the evening when they are sluggish, or spray plants with insecticidal soap or neem oil.
Prune Tomato Suckers
Indeterminate tomato plants produce many suckers -- new shoots that start where a branch connects with the main trunk. Removing suckers will decrease the number of fruits produced, but the remaining tomatoes will be larger and will ripen sooner.
Control Apple Maggots
To prevent apple maggot adults from laying eggs on developing apple fruits, place red, sticky spheres (available from nurseries) in trees to fool the adults into landing on these fake apples, where they will die. Place four spheres per dwarf tree, and check them every few days to clean off the moths.