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Mosquitoes at sunset. (Getty Images)
Mosquitoes at sunset. (Getty Images)
Master Gardener columnist Laura Simpson at the Press-Enterprise in Riverside on Thursday, January 17, 2019. (Photo by Watchara Phomicinda, The Press-Enterprise/SCNG)
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Q. Why are there so many mosquitoes this year? I’ve never seen so many or been bitten so many times before!

One of the reasons California weather is so desirable is the (mostly) mild temperatures coupled with low humidity. Most other southern states that have mild winters have high humidity during the warm summer months. That high humidity is, unfortunately, very favorable for all of the icky insects that we usually don’t see here. Flies, cockroaches/palmetto bugs, mosquitoes, and other bitey things thrive in warm humid environments. Although the unexpected storms we experienced this summer were nice for our lawns, they had some unpleasant side effects.

Mosquitos and flies enjoy humidity. Flies are attracted to bare soil and are especially attracted to bare soil that is moist. When we removed our builder-installed turfgrass, we noticed that the fly population greatly increased until our buffalo grass lawn was established.

Mosquitos need standing water to multiply. Many people don’t realize how little water is needed for the mosquito population to explode.  Neglected swimming pools, bird baths, and inactive fountains are the first suspects when trying to determine the source of a mosquito population explosion. Our unusually heavy rainfall may have produced other, less obvious, breeding sites. A forgotten bucket, a recycling receptacle containing cans or bottles, a shovel left out in the garden, or anything capable of holding even a small amount of water can provide an ideal location for mosquitos to breed.

Check around your property for any standing water. Inspect your window screens for any tears or holes. Use a mosquito repellent that has DEET as an active ingredient, since this is the most effective way to avoid bites. Some plants, such as citronella-scented geraniums, are advertised as mosquito repellent. This may be the case, but after you’ve been bitten several dozen times, you’re probably more interested in just killing the darned things.

If you’ve been bitten, the sometimes intense itching can be relieved by applying cortisone cream or Benadryl lotion. I’ve discovered that battery-powered heat treatment devices are very effective in stopping the itch, so I highly recommend them. Just hold the heated disc against the bite and press the button. The disc heats up to 140 degrees for 3-5 seconds, which reportedly neutralizes the protein that causes the itch. The temporary discomfort results in immediate itch relief.

Q. I keep finding these weird, bumpy brown things on my outdoor pots and walls. Could they be praying mantis egg cases?

Female praying mantises (or mantids) will deposit their eggs, often on vertical surfaces, in the fall. Mantids live throughout the lower-elevation areas of California and, although they are common, it’s always a thrill to me to encounter one in my garden. I think that’s because they are so superbly camouflaged that I don’t see them unless they start moving. 

Although females sometimes kill and eat their mates, this is not always the case and is certainly not a necessary step for successful reproduction. Remember, “take out” can mean food, dating, or murder and, if you’re a praying mantis, it can mean all three.


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; https://ucanr.edu/sites/RiversideMG/

San Bernardino County

mgsanbern@ucanr.edu; 909-387-2182; http://mgsb.ucanr.edu