Here are this week’s gardening questions and answers, provided by Parker County Master Gardeners. To submit a question, send it to email@example.com. For more information about Parker County Master Gardeners, or to become a member, call 817-598-6096 or visit www.pcmg-texas.org.
Aphids have invaded my newly planted vegetables. What is the safest method to treat them?
Aphids are tiny insects that congregate on the bottom side of leaves and suck the fluid out of your plants. Almost every plant has one or more aphid species that occasionally feed on it. When aphids feed in large groups, they can cause leaves to curl and turn yellow, and stunt the growth of new shoots. They also secrete a sticky substance known as honeydew, which often turns black with a sooty growth of mold.
While larger plants can tolerate light to moderate levels of aphids, they can significantly damage a young and tender plant. In a vegetable garden, an insecticidal soap is the best choice. This product kills primarily by smothering the aphid, so thorough coverage of infested foliage is required. Follow all instructions carefully.
I have been finding snail shells in my flower garden and expect that I will have problems with these pests soon. What can I do?
Snails and slugs rank right up there with the some of the most bothersome pests in the landscape. They are most active at night and on cloudy or foggy days. Often the only clues to their presence are the silvery, slime trails and the smooth-edged holes they leave behind on my plants.
On hot days, snails attach themselves to shady surfaces. The first step is to eliminate these hiding places. Boards, stones, leafy branches growing close to the ground, and dense ground covers such as ivy are ideal sheltering spots.
You won’t be able to remove everything; however, a smart gardener might think of each hiding spot as a trap. The underside of a board will attract nearby snails for easy removal at your convenience. An inverted melon will do the same. A small cup filled with beer will trap and drown them. Make a regular practice of trapping and removing snails and slugs from these hiding places.
Switching from a sprinkler to drip irrigation will reduce moist surfaces and make the area less desirable. A copper barrier around your plants will kill them by short-circuiting their nervous system.
Though baits can be part of a management program, it is better to use them in conjunction with these simple garden modifications.