Controlling Landscape Pests Using Integrated Pest Management

April 3, 2016

Usually the first thing that pops into our minds when we have a pest problem is to spray a pesticide, but pesticides should be used as a last resort after all other pest control options have been tried.  Pesticides cost money, can harm people, pets and the environment; and pests can develop immunity to them when they are over used.  A better approach for controlling pests is to use integrated pest management which uses a variety of methods including cultural, mechanical, biological and chemical controls.

Most of the time pest problems start with incorrect cultural practices, meaning the wrong plant was put in the wrong place, or it is not getting the conditions that it needs to do well.  So the first thing is to check and make sure it is the right plant in the right place and it is being taken care of correctly. 

Once you’ve determined the plant needs, next consider what is going on around the plant or plants.  Is it getting too much water?  Is there a downspout from the gutter system that is pouring lots of water in that location?  Is it a low lying area?  How often is it being watered?  Providing proper soil moisture is important for plant health.  Over or under watering can be detrimental.

If plants are chosen correctly for the site, they should be able to do well on rainfall only once they are established.  Supplemental water may occasionally be needed during times of extreme drought.  Springtime, especially April and May, and sometimes October and November are usually the times when extra water may be needed by plants to keep them looking their best.  Remember to only apply ½ to ¾ inch of water per irrigation because applying more than this amount of water is wasteful, and washes nutrients and chemicals past the roots and into the groundwater.

Disease incidence can be reduced by watering in the early morning when dew is present.  Watering during the dew period will wash away fungal spores, and as the sun rises it dries off the plant.  The longer a plant stays wet the more likely it is to become diseased. The goal is to reduce the amount of time a leaf is wet.  Plants crowded together with little to no air movement can also promote disease.  Good air movement is important for keeping plant leaves dry and thus reducing disease incidence.

Florida’s very sandy soils don’t hold onto water, nutrients or chemicals.  Improve the soil by mulching.  As organic mulch breaks down it adds organic matter to the soil, and also releases nutrients very slowly for the plant to use.   Mulching helps keep the soil moist, keeps the soil temperature from getting very hot or cold, reduces runoff, and helps keep weeds from sprouting.  Just remember to keep mulch away from the base of plants, and replenish the mulch as needed to keep it about 2 to 3 inches thick.  

Remember, to choose the right plant for the site you must consider the acidity or alkalinity of the soil.  In coastal areas the soil tends to be alkaline and this can cause nutritional problems for acid-loving plants like gardenia, ixora, and azalea.  Always get a soil pH test to determine the acidity or alkalinity of the soil before choosing plants, or if you see micronutrient deficiencies occurring.

Too much of a good thing, like water and fertilizer, promote very rapid growth.  This rapid growth creates very succulent leaves and stems, which is a dinner bell for bugs.  In addition to bug problems it also creates a lot of pruning – two things you don’t want.  It is better to strive for slow growth by using slow-release nitrogen fertilizers or letting organic mulch decompose and release nutrients slowly.  The more you water and fertilize plants, the more maintenance you will have to do.

Mechanical or physical controls are also a method of pest control.  Mulching suppresses weeds, pruning removes diseased portions, and picking pests off of plants are all physical pest controls.  Look at plants you are getting ready to purchase and if you see any bugs, diseases, or weeds leave those plants at the nursery and don’t bring those problems home with you.  Only use local fire wood because there are some very bad wood boring pests than can easily get moved around in this wood.

Biological control is another form of pest control.  There are all kinds of insect predators, parasites and pathogens that will attack and kill insect pests.  I’m sure you’ve heard of ladybugs, but there are also minute pirate bugs, green and brown lacewings, assassin bugs, damsel bugs, big-eyed bugs, parasitic wasps, predatory wasps, mites, stinkbugs and more.  There are also beneficial fungus and nematodes. 

Cultural, mechanical and biological control measures should be used on a continuing basis.  If all of these methods fail to control a pest to an acceptable level then a pesticide may be used.  First use those pesticides that are least toxic to biological control organisms and those that don’t remain in the environment for a long period.  Insecticidal soaps, and horticultural oils are good for controlling aphids, mealybugs, scales and whiteflies.  Bacillus thuriengensis only controls caterpillars and does not harm other insects. 

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