If you are growing strawberries in your garden, eventually, you'll likely come across some pest causing damage to them. While birds are a common annoyance for anyone growing berries, there are also several insect pests that can be a problem for those of us growing strawberries. The most common strawberry pests are slugs, strawberry bud weevils, tarnished plant bugs, and spittle bugs.
Strawberry Pest #1: Slugs
If you're seeing small, deep holes in the strawberry fruits, usually under the cap, chances are good that you're dealing with slugs. They also leave tell-tale silvery slime trails that can often be seen on the foliage. Slugs generally cause damage at night and are more of a problem during damp weather.
To prevent slug damage on your strawberries, remove leaves, mulch, and other plant debris from the area to avoid giving the slugs an easy hiding place. Avoid having the soil's surface constantly moist (which only encourages slugs) by watering less frequently, but deeply.
You can trap slugs with a board or citrus rind trap. Just be sure to check the trap each morning and remove any slugs, or they'll be right back to eating your strawberries again the next night.
Strawberry Pest #2: Strawberry Bud Weevils
Strawberry bud weevils are also sometimes called strawberry clippers. They are about a tenth of an inch long and reddish brown in color with black patches on their backs. Like most weevils, they have a pronounced curved snout.
Strawberry bud weevils are a problem in early spring when the adults emerge from overwintering. They use their snouts to puncture the strawberry flower buds and feed on the pollen. Then the females lay a single leg in each bud and girdle the bud to prevent it from opening. This protects their larvae but also destroys any chance of that blossom becoming a berry. These blossoms will usually fall off, or hang limply from the plants. The eggs hatch after a week, and the adults emerge from the infested blossoms after three to four weeks.
Start checking for weevils as soon as strawberry plants form buds. Remove any infested buds, as well as any that have fallen to the ground, to eliminate having them winter over to infest another year's crop. You can spray your plants with insecticidal soap if you see the weevils, but repeated applications may be required.
Strawberry Pest #3: Tarnished Plant Bug
Tarnished plant bugs are gray or brown, oval, winged insects. They have a brassy or "tarnished" color. The adult females emerge in spring as strawberry flower buds appear, and they lay eggs. The nymphs hatch and feed on the blossoms and developing strawberry seeds. When they feed on the strawberry seeds (which, of course, are on the outside of the berry) it results in misshapen fruit.
To control these pests, remove weed and other plant debris near your berry patch. Also, try to keep the garden as weed free during the blooming and fruiting season as possible. Check plants at least a couple of times per week before they start blooming for signs of tarnished plant bugs. Insecticidal soap can be used if you see the bugs on your plants. Any fruit showing damage should also be removed; it will not grow properly.
Strawberry Pest #4: Spittlebugs
Spittlebugs are very easy to identify: if you see a clear, bubbly foam at the base of your plants, you have spittlebugs. They produce this foam and hide in it.
Spittlebugs harm plants by puncturing the stem and feeding on the juices in it. Most of their damage occurs near ground level and results in small berries and/or stunted, weak plants. The good news is that any damage caused by spittlebugs is temporary, and the plant will survive and grow another year.
The best way to control them is to pick them off of plants (just look for that tell-tale spittle -- they're in there) and squish them. Check plants regularly, and destroy any spittlebugs you see.