Gardening: Dealing with mosquitos in a wet August
August is here and temperatures this month will have highs of about 90-95 and lows in the mid-70s. With more than eight inches of rain this is usually one of the wettest and most humid months.
Keep in mind that though it may be a wet month, transpiration is very high during the hot weather. I wrote about this in another column. Transpiration is a plant process in which water is absorbed by the roots, passed through the vascular system and exited from the plant into the atmosphere. It is a process which cools the plant much like perspiration cools us. This means lawns and plants need large quantities of water more frequently in the hot summer. So be alert for signs of insufficient water between rain showers and keep your sprinklers on to avoid damage.
This has not been a bad year as far as mosquito populations are concerned. There are diseases carried by mosquitos. With a lot of rain the mosquitos can increase in numbers. It is very important for everyone to check for any places around your home or business where water collects as you may be raising mosquitos. You should get rid of old tires, buckets and other containers, or you should keep them empty of water. Repair leaky outside faucets and move air conditioner drain hoses frequently to avoid damp soil. Also change and scrub bird baths or watering pans for pets at least twice a week.
Don’t discard your bromeliads. Instead treat the cups every couple of weeks with Thuricide which will kill the larva or rinse them out with water. All the mosquito species require water for breeding. Mosquito larvae are not adapted to life in moving waters so circulating ponds should not be a problem. They occur instead in quiet water. Since half the land area of Florida is subject to flooding, mosquitos breed in large numbers throughout the state. Mosquitos do not breed in the heavy undergrowth of weeds or shrubs.
Although these places offer excellent refuge for adults as anyone gardening can attest, they do not provide a suitable habitat for mosquito larvae. The populations of mosquitoes have lowered dramatically on Marco Island. I believe it is due to all the shrub spraying people do around their homes. While I don’t think this bodes well for our beneficial insect populations it is a blessing in disguise as far as mosquito populations are concerned. In addition to freshwater mosquitos, we are surrounded by mangrove islands which is a great breeding ground for the salt marsh mosquito.
The wet weather of August also provides ideal conditions for the growth of fungi. Root- rot, leaf spot, stem rots and rust are a few disease problems on lawns and shrubs which are fueled by the heavy rains. Remove diseased leaves and stems from the garden and apply a fungicide to prevent fungus from infecting healthy tissue. And, remember to clean your pruning tools with a mild bleach solution to prevent spreading disease while cutting healthy tissue with those same tools. Take-all Patch is a serious lawn disease which can cause your lawn to melt away with the heavy rains.
Caterpillars are around in great numbers this time of year. You may also notice large numbers of sod webworm moths flying from St. Augustine lawns. Stinging caterpillars are also probably around right now. Several varieties of stinging caterpillars can be found on shrubs and trees including the I.O., saddleback, puss and hag. I have dedicated columns on these nasty caterpillars. The sting comes from the spines on their backs which are connected to poison glands. Their sting is extremely painful and can cause severe allergic reaction in susceptible people. These caterpillars can be controlled with Thurified or Seven.
Scales and whiteflies are also active on ornamentals causing sooty mold. Treat with horticultural oil, Merritt or Tempo for control. Chinch bugs, sod webworms and grubs can all damage your St. Augustine lawn this month. Treat as needed with Tempo or other products labeled as effective on chinch bugs, Dylex for grubs and Dipel for the sod webworms.
If you see a white web on the branches and trunks of your trees, don’t be alarmed. It is a psocid, a tiny insect that feeds on the algae on the trunks of many trees. They spin the web for protection from those August rain showers. There is no need to treat for this problem.
It is best not to fertilize your lawn in August. If you feel you must fertilize St. Augustine use an organic such as milorganite or iron for a greener color. Do not use a high nitrogen fertilizer now as it will fuel bug and disease problems. It can also make the lawn more susceptible to water stress which can be a problem in times of high transpiration as the rapidly growing grass requires larger quantities of water.
When there have been heavy rains the acid loving plants like ixora, gardenia and azalea could use a feeding this month to carry them through their blooming period. Don’t forget to feed rose bushes regularly as well. A good nutritional spray can be helpful for all your plants at this time. Nutritional sprays trans-locate directly through the leaves and so avoids the problem of leaching through the soil which can occur with heavy rains.
The last pruning of the poinsettias must be done before September if there are to be flowers (or colorful bracts) in December for the holiday season. You also should not do any more severe pruning of gardenias beyond August as you will remove the old growth required for flowers in the spring.
Prepare your flower and vegetable beds for fall planting. Rid the site of nematodes and disease using clear plastic solarization or fumigants. Add organic matter to the soil and then let it rest in preparation for fall planting in October and November.
It is unbearably hot out there in the garden, but you need to put on a good hat and your sun screen and stay on top of your gardening or the bugs, diseases and weeds will take over.
Eileen and Peter Ward have owned a landscape and lawn maintenance company for 35 years. Eileen can be reached at Gswdmarco@comcast.net or 239-394-1413.