Question: We seem to be finding earwigs everywhere! We find them both inside and outside the house. How do we get rid of them?

Answer: Earwigs often cause alarm when discovered indoors. They have a frightful appearance, move rapidly around baseboards at the ground level, and may emit a foul smelling, yellowish-brown liquid from their scent glands. The common name earwig, comes from an old European superstition that the insect could enter the ear of sleeping people and bore into their brains. They cannot.

Earwigs are active at night. During the day, they hide in moist, shady places such as compost piles or beneath stones, boards and debris. They can sometimes be found in homes, particularly in the summer, but they do no damage to the house or its contents. They rarely fly but can move rapidly, or can be moved by lumber, cars, luggage or other means. They are attracted to lights.

Earwigs feed primarily on decaying organic matter and are quite beneficial in that they also consume other small insects. Unfortunately, they also like to chew small holes in the leaves and tender shoots of many garden flowers such as marigolds, hollyhocks, dahlias, zinnias, asters and gladiolus. In vegetable gardens, they can also be a problem on seedlings of lettuce, celery, cole crops, beets, corn, beans, carrots and others.

Earwigs need and are very attracted to moisture. High population, practically invisible during the day, may be present around foundations, in landscaped yards, in mulch, under boards etc. Be sure to eliminate damp, moist conditions in crawl spaces under houses around faucets, around air conditioning units and along house foundations. Earwigs are strongly attracted to fish oil and to some extent vegetable oil. Insects can be trapped by filling shallow containers with the oil and burying it in soil up to its rim.

Carbaryl (Sevin) dust provides an effective control when applied to the soil surface when earwigs are first noticed.

Question: We seem to be getting conflicting information on whether we should or should not lightly sprinkle our plants on hot days to cool them off. Some garden books suggest we do this, while others say the water acts as a magnifying glass and will result in scalding the foliage. Which is correct?

Answer: Your question is certainly appropriate this time of the year when we experience some of the warmest temperatures of the growing season. Research conducted at the University of Arizona found that it is difficult to establish whether “sunscald” and other solar induced leaf injuries are caused by solar radiation alone or by a combination of factors such as extreme temperature fluctuations, excessive temperatures, and adverse water relations.

“Sun-scalds,” physiological disorders characterized by red or brown pigmentation of the plant tissue followed by internal breakdown and death of damaged tissue, are prevalent after hot, dry periods followed by sudden applications of water. According to Professor Richard Harris, who conducted the research, landscape plants in dry soil often have leaf temperatures 10 to 25 degrees F. above ambient air temperatures. Leaf temperatures are often as high as 104 degrees F. with little or no permanent leaf injury at these elevated temperatures.

Professor David Martsolf of the University of Florida hypotheses that mid day sprinkling during hot weather may be detrimental due to a rapid decrease in plant temperature. If sprinkler irrigation water is applied during a hot, mid-day period when the leaf may be stressed and the stomates closed, the stomate guard cells may regain turgor and the stomates open. The leaf interior might lose so much moisture as to be more severely damaged then if the stomate had remained closed.

Based on research it would appear that mid-day sprinkling does indeed cool off plant leaves. At the same time, it may well result in some leaf damage.

Related research at Oregon State University, found that maintaining adequate soil moisture at all times around rhododendron plants will prevent sunburned foliage. Irrigation to cool leaf temperatures was not necessary to prevent sunburn.

EDITOR’S NOTE: For answers to local gardening questions, contact Master Gardener Rachel Gana at 642-8723 or e-mail her at: baiter1@pacifier.com.