12 Common Garden Pests in Arizona and How to Treat Them
A few billbugs won’t ruin your garden, just like a couple of blister beetles won’t plow through your flowers in a week. But ignoring pests can lead to infestation, which may become costly or require professional help.
Here, we will explore the 12 most common garden pests in Arizona and how to deal with them.
1. Squash Bugs
Squash bugs are tiny, even upon reaching adulthood, so hand picking is one of the best ways to deal with smaller groups. They reproduce fairly quickly (typically within 10 days), although a full-blown infestation could take months to develop.
Water your plants and keep them healthy as a best preventive measure. But also try to actively hunt for eggs under the leaves of your plants and flowers. Infestations can be dealt with through natural pesticides, although power-washing sturdier plants combined with handpicking is usually enough to prevent them from amassing in larger numbers.
2. Spider Mites
Spider mites are so small that they are barely visible without a magnifying glass. That’s why all gardeners should frequently check their weaker flowers and plants—one of the most obvious signs of spider mite infestation is leaves turning yellow.
Given that spider mites normally attack weaker, unhealthier plants, power-washing is not a viable option, as it will ultimately damage the plant even further. Use a shower faucet on a hose and apply less water pressure to dislodge them from affected plants.
Apply neem oil or a similar natural insecticide to prevent spider mites from returning to the flowers. Larger infestations will develop immunity to natural insecticides over time, so insecticidal soap is ideal.
3. Cushion Scales
Cushion scales are arguably the least conspicuous plant pests and are nearly impossible to miss. They typically move in larger numbers and build colonies in areas where they feel secure. Your No. 1 priority should be finding and destroying them.
Vedalia beetles actively hunt cushion scales and will not affect garden plants, making them excellent allies. Sticky tapes can preventinfestations while natural predators (vedalia beetles) are best at wiping out stragglers. Cushion scales are fairly resistant to insecticides.
You may notice that ants in your garden will slightly change their usual routes once cushion scales start nesting. This is due to the honeydew produced by the pest. The ants will protect the cushion scales to ensure they can continue to harvest the sweet, sticky substance. To keep the population from rapidly increasing, search for scale crawlers near places where ants typically gather.
Mealybugs tend to suck the sap from host plants, which weakens and ultimately kills the plants. Mealybugs also secrete honeydew, which attracts ants that will try to protect them from predators. So attracting companion insects is less efficient in this case.
Mealybugs often hide in hard-to-reach places, usually at the base of the stem or under leaves. Soak cotton swabs and Q-tips in alcohol and wipe the plant stems, taking care to get all the nooks and crannies. Alcohol kills them on direct contact. Repeat daily as necessary until all are gone.
Managing thrips is easy if you catch them early. Black specks and circles on the plant are signs of a thrip invasion.
Isolate attacked areas and prune them. In most cases, making a habit out of this will prevent infestations from spawning. Insecticidal soaps and neem oil work well on larger numbers, while natural insecticides can tackle smaller swaths.
6. Harlequin Bugs
Harlequin bugs reproduce at a rate that is similar to squash bugs, although they need significantly more time to hatch (up to 29 days). These winged pests are fairly agile and almost impossible to hand pick, making them challenging to eliminate.
Fortunately, guineafowls are effective at preventing infestations. Insecticides can harm the already weakened plants, making them more susceptible to toxic damage.
Use ‘trap crops’ (kale, mustard and turnips) to attract the majority of pests to one area to deal with them more efficiently and prevent recurring infestations.
Lacewings aren’t as much of a threat as some other pests, but their rapid breeding habits may cause issues in your garden. Lacewing eggs hatch between three to 10 days, and the larvae can breed and feed simultaneously.
Hand pick the tiny bugs off of the plants or, even better, user a power washer to remove them en masse. Natural insecticides also work well, especially if used on relatively sturdy plants.
Termites are resistant to most natural pesticides; power-washing will not kill them; and handpicking isn’t recommended since they are prone to attacking humans. Fipronil is one of the most effective chemicals and is used in most liquid termiticides alongside hexaflumuron. Although you may have to sacrifice a plant or two in the process, these are the most effective ways to treat termites.
9. Blister Beetles
Just like termites, blister beetles are known for being hostile towards humans. They usually come in large numbers, so preparing for an infestation ahead of time is recommended. Hand pick isolated beetles while wearing gloves, and keep a watchful eye on your garden’s edges, as this is where they typically nest.
Attracting birds to your garden is the best way to properly manage infestations without exposing yourself to risk. Consider insecticides if all else fails.
10. Palo Verde Beetles
Palo verde beetles typically nest in tree trunks, so you prevent an infestation by destroying their eggs. Wear gloves while hand picking isolated beetles—they bite—and use natural insecticides to keep them off your plants.
Contact pesticides work best against billbugs because their sturdy chitins make them more resistant to sprayed chemicals. Hand picking isn’t recommended unless you are wearing heavy-duty gloves. Large-scale infestations are rare, as billbugs are not as small and adept at hiding as most garden pests.
Low-grade insecticides can kill off nymphs. Spinosad is recommended for exterminating adults. Ground beetles are their natural predators, although risky, as they may attack your garden plants. Attracting birds is a safer, although a slower, solution.