Every year the same symptoms seem to appear in late July through August resulting in numerous holes in the leaves of our garden plants. Most often these are discovered in our shade gardens where we rely on foliage plants to make a statement. We all know what they are caused from; they are caused from the elusive slugs that seem to feast on vegetation during the nighttime hours while we are all fast asleep until morning.
Slugs are categorized as snails without shells. They range from about a half-inch up to 2 inches in length and are gray or brown in color. They are most active during the nighttime hours when the temperatures are cool and there is a heavy dew that seems to assist them in moving across the ground a little more stealthily. As they move, their body excretes a slime trail to glide them along to their feeding sights. Slugs have slender eye stems on their heads and mouthparts that are file-like to rasp away at plant tissues causing irregular-edged holes.
Early on, one will notice small holes in the leaves, but as time goes forward these holes become more numerous and create a visually displeasing effect, but often do not cause the demise of a perennial plant. Annuals that lose too much foliage can become stressed and eventually succumb to the damage.
Slugs also feed on fruits and vegetables that may be in cool damp areas. Tomatoes that sit beneath the foliage and rest on the ground are prime candidates. Cucumbers, peppers, squash and melons can also be victims to these critters, so watering in the morning is best in preventing slugs from feeding on these tender produce items.
Prime locations for slugs are in areas that receive a fair amount of shade, places that stay cool, and those that are often damp. Areas that have a great deal of organic materials and leaves that touch and shade the ground are perfect areas for slugs to reside, especially after a rainfall or garden watering. When the days are hot and dry, slug activity is at a low.
So how does one avoid slugs or lessen the damage they create? There are many preventative things one can do in the garden. Watering in the morning hours so the area dries out by evening can help in many ways. Removing plant debris and leaves that may hang upon the ground surface will also assist in moving air through the lower regions to keep them less moist. Thinning out areas of the garden where the plants are too close together is also a helpful tool, which once again allows air to circulate through the plant bases.
There are many natural predators of slugs such as snakes, beetles, frogs, turtles and birds. Many enjoy feasting on their soft bodies during the day and night. Of course, there always seems to be more slugs than available predators so often, other means are necessary during heavy infestations.
There are also organic and chemical methods available to control slugs. One of the most user-friendly options is simply laying out thin boards in the areas where heavy feeding occurs. In the morning hours, simply lift the board and pluck up the slugs to discard. Wet newspapers also work well for this option, but it is a bit time consuming and you have to touch the slugs.
Crushed eggshells spread out beneath the susceptible plants tend to scratch their bellies while they try to move across the ground and hinder them from going further, moreover acting as a deterrent. Sluggo is a natural product that kills slugs, but does not harm wildlife and is simply iron phosphate that breaks down into fertilizer within weeks.
Some have said that slugs also enjoy a good party, so flat tins of beer with the rims at ground level seem to attract quite the group due to the scent. I have heard that they prefer cheap beer and go swimming, but since they cannot swim they tend to die right there in the pan making for easy removal from the garden.
Another way to prevent slug damage is to choose slug resistant plants in the shade gardens such as blue hostas with thicker leaves, astilbes, vincas, coralbells and hydrangea to name a few. Thin-leaved hostas, lungworts, along with annuals such as begonias and coleus can tend to be more tender and susceptible to damage, so keep an eye on these selections.
Slugs can cause damage and be a bit frustrating, but just because they are numerous one year does not denote that they will be numerous the following. Each year is dependent on garden and weather conditions that seem to enhance or hinder their survival rates.
Take the route that works best for you in the garden which will satiate your situation. There are plenty of natural ways of fighting this pest without adding harsh chemicals to your environment. By fighting with a natural item, you do not harm the other natural predators out there that will eat them also. Good food for thought.