Yuk, They’re Back!

Posted: May 9, 2015

Do you have silvery mucous trails in your garden? If you do, you may have slugs. These slimy trails and slugs lurking in your plants and vegetables are unappealing and unappetizing.
Photo Credit: PSU Entomology Dept.

Photo Credit: PSU Entomology Dept.

Slugs are mollusk. They glide along on a muscular “foot” which constantly secretes mucus, which provides ease of movement and later dries to form this “slime trail.” In Pennsylvania, slugs come in all sizes, some as large as eight inches. All are hermaphrodites (having both male and female reproductive organs) so each slug can potentially lay up to 80 eggs up to six times a year. Predators of slugs are snakes, toads, birds, beetles and humans.

The first step in outsmarting slugs is to understand their habits. Eggs overwinter and grow in areas that are protected, such as under boards, plastic and decaying vegetation. In the spring slugs become active, especially at night and on cloudy days. They feed on a variety of living plants including fruits and vegetables, especially seedlings and low-lying crops such as strawberries and tomatoes. Many plants are resistant to slugs, such as lavender, begonias, geraniums and woody ornamentals.  

Control should be started early in the spring to prevent damage. Because slugs are nocturnal, visit the garden after dark with a flashlight. Kids love to help with this. Using rubber gloves, handpick and place slugs in a plastic bag, seal and dispose in the garbage.

Traps can be used to collect the slugs. Use wet newspapers, boards or burlap in the evening and collect the slugs in the morning. Slugs are attracted to inverted sweet melon rinds that can then be discarded, slugs and all. Beer traps can also be used. Traps can be made by using shallow dishes recessed to ground level filled with beer. Some people have used beer-filled cottage cheese containers with lids. Ground level holes are cut in the sides of the container for the slugs to enter, fall into the beer and drown. The deeper dish can help slow evaporation. You can also purchase beer traps online and in garden centers. (Beer traps will only attract slugs within a few feet making this method labor intensive.)

Iron phosphate is a common granular bait found in garden centers under names such as Sluggo or Escar-Go. It causes the slugs to stop feeding and is best used when the slugs are actively feeding above the surface during periods of high humidity. Iron phosphate is safe to use around children and pets, unlike toxic bait products with metaldehyde. When using chemicals always follow directions on the label and dispose of properly.

Diatomaceous earth contains diatom fragments that have sharp microscopic glass-like edges that will damage the slug’s outer water-protecting cuticle causing it to lose water. However it only works in dry conditions. Copper strips and flashing can provide a barrier and can help to deter slugs. It can be purchased in garden shops or online.

Finally one of the best ways to manage slugs is to make your garden uninviting in the first place. Practice good hygiene to discourage slugs. Remove any debris, including boards, plastic, weeds, ivy or rotting vegetation that provide shelter for the slugs or eggs to make a home. Using drip irrigation rather than sprinklers also makes conditions less favorable for slugs.


Contact Information

Peg Jones
  • Luzerne County Master Gardener