Q - I have a problem every year trying to grow squash, cucumbers and pumpkins in our garden. The plants come up fine, but once they get six to eight inches long, they start dying. Can you tell me what is causing it?

A - The squash vine borer is a serious pest of cucumbers, pumpkins, cantaloupes and squash. The larva stage of the borer overwinters in a cocoon just below the soil surface. A clearwing moth emerges in the spring and lays eggs on the stems of the plants. The borers hatch and chew their way into the stems to feed. Parts of plants and whole plants may be killed. Dusting with methoxychlor may provide some control. Directions on the label should be followed closely. The borer is creamy white and about an inch long. When the vine starts to wilt, kill the borer, and put about an inch of soil over the stem where the borer was. Roots may develop and the plant may grow and produce.

Q - My sycamore tree is losing most of its leaves. The same thing is happening to two trees planted along the street. Do you know the cause?

A - It is due to a disease called Anthracnose, which can be very serious with cool, wet spring weather. The fungus will become inactive when the average daily temperature reaches 60 degrees.The fungus causes a dying area along the larger veins of the larger leaves. Eventually the whole leaf is killed and falls. The tree usually gets new leaves. There is no practical way to control the disease. The best thing you can do for the tree is remove the leaves that fall, fertilize the tree and water it during dry weather this summer.

Q - I bought some Northern Spy cooking apples last winter and saved the seed to start my own trees. Who do I go about it?

A - Seeds of apples and most other tree fruits do not produce plants similar to the parents. Usually they are inferior, but one in 5,000 may be very good. Since it takes several years from the time the seeds are planted until the tree bears fruit, it will be a long time before you know whether or not you have something. If it's fruit you want, it may be much better for you to buy and plant named varieties that you know will produce the quality you desire.

Q - When is the best time to plant lettuce seed for late summer and fall harvesting?

A - Mid- to late August is a good time to plant lettuce for a fall crop.

Q - Can you tell me what is killing my redbud tree? Almost overnight the leaves turn brown.

A - In many areas the redbud tree, sometimes called the Judas tree, is very susceptible to a canker disease, and because of it very few large redbuds are seen. The infection occurs, the tree becomes girdled and the part of the tree above it dies. Removing the diseased part, if discovered early enough, may prevent destruction of the ornamental value of the tree. Cut it off about two inches below the diseased part.

Q - The tree man who looked at my two maple trees told me the best way to fertilize a tree is to punch holes in the ground and put fertilizer in them. Is it actually necessary to do it this way?

A - The fertilizer can be spread on the ground around the tree, or it can be put in holes. If it is put in holes, it will be available to the tree roots much sooner. F. R. Gouin, University of Maryland horticulturist, says: Mother Nature feeds her trees by simply dropping leaves on the ground. These rot and release their nutrients into the soil and back to the roots. If the tree is growing in a lawn area, I recommend that the homeowner add additional fertilizer under the drip line of the tree and slightly beyound. Let Mother Nature wash the fertilizer down near the roots in her slow but methodical wway.

Q - Is there a biological way to prevent crabgrass from growing in the lawn?

A - Since crabgrass seeds need light to germinate, cutting the grass at 2 to 2 1/2 inches will shade the ground and prevent the weed seed from germinating.

Q - I have a Peace Rose in my garden that is 12 years old. Two years ago I noticed a different type of rose growing on the left side of the bush. It seems to be a red climber. What would cause two different types of roses to bloom on one bush?

A - Almost all roses sold today are propagated by budding. A bud of the desired variety (the Peace Rose, for example) is grafted onto the roots of a form of wild rose. The reason for such a practice is that the Peace Rose might not survive a rough winter if it were on its own roots.

Sometimes a shoot may develop from the root stock, and it will take over if allowed to grow. It should be removed as soon as it is discovered. Don't just cut it off at ground level, but remove some soil and get all of the shoot. Otherwise, it will be right back again in a short time.

Q - I have a small crape myrtle and a small magnolia, both two years old. I do not have much room and would like to keep both of them small. Is it okay to prune them pretty heavy?

A - The crape myrtle can be cut back almost to the ground in late winter every year (or less severely) and it will bloom in the summer of that same year. The magnolia will respond poorly to heavy pruning, particularly the evergreen variety. If you can't give it room enough to develop and grow properly, better get rid of it and save youself the agony of watching it die slowly.

Q - Will planting trees and shrubs around my house help reduce the heating bill next winter?

A - Studies have shown that windbreaks and evergreen foundation plantings can cut winter fuel use by 10 to 30 percent.

LILY SHOW IN MIDDLEBURG

The Garden Club of Virginia will hold its 37th annual lily show this Wednesday (3 to 9) and Thursday (10 to 3) at Foxcroft School in Middleburg. A green offering will be requested at the door.