Q: What can I do to keep grasshoppers out of my garden? They are really destructive!
Grasshoppers are tremendously destructive and difficult to control. In late fall or early winter, the female lays her eggs in undisturbed ground (open fields or grasslands, mostly). Once the weather warms up, the eggs hatch and the hungry nymphs start eating whatever they can find. After about 5 or 6 molts, they become bigger, hungrier adults. The mature grasshoppers live for 3 months and produce only a single generation per year. Every 8-10 years, usually after a particularly wet winter, you will see a really bad infestation that can last several years.
Unfortunately, there is no pesticide available to homeowners that is completely effective against grasshoppers. Carbaryl-containing bait formerly was widely used but is now only available to licensed pest control operators. The protozoan Nosema locustae, also used in baits, is only effective against one species of grasshopper, and only effective against the young nymphs.
Mechanical barriers, such as row covers, are only effective if placed before the grasshoppers arrive. Hand-picking is tricky (unless you do it in the morning when they are still cold and sluggish).
In this case, relying on natural predation is probably your best bet. Many birds, such as the Western bluebird, robins, kestrels, owls, roadrunners, chickens, quail, and many songbirds will eat grasshoppers. They are also a favorite snack for cats, dogs, and other mammals.
Q: Something is eating my lettuce. My backyard is fenced in, so I don’t think it’s rabbits.
It still may be rabbits. Check your fence and gate for any gaps — critters can squeeze through some surprisingly small spaces.
Is lettuce the only crop being eaten? If you have tasty things growing on a trellis and they are being eaten as well, you probably have rats (which are worse).
Do you see rabbit pellets in the garden? (That’s one of two things that rabbits do best.) Other possible culprits would be opossums or racoons. If you’re certain that your nighttime visitors are rabbits, a chicken wire fence may be sufficient to exclude them.
Sometimes you may be surprised. We thought the local scrub jays were eating all our grapes until my daughter heard rustling in the grapevines late one night. We shined a flashlight in the direction of the noises and seven little masked faces popped out.
Another year, we were puzzled because we had a beautiful pear tree that was producing fruit but was bare when it was time to harvest. We thought it might have been a neighbor (or raccoons again). One evening I heard a crunching sound coming from the tree. I retrieved my handy flashlight and saw about a dozen opossum tails hanging straight down, like icicles, out of the tree canopy.
Moral of the story—make sure you know for sure who the culprit is before taking corrective action.
Los Angeles County
mglosangeleshelpline@ucdavis.edu; 626-586-1988; http://celosangeles.ucanr.edu/UC_Master_Gardener_Program/
Orange County
ucceocmghotline@ucanr.edu; http://mgorange.ucanr.edu/
Riverside County
anrmgriverside@ucanr.edu; 951-955-0170; https://ucanr.edu/sites/RiversideMG/
San Bernardino County
mgsanbern@ucanr.edu; 909-387-2182; http://mgsb.ucanr.edu