JoAnne Skelly
This is the time of year where we notice damage to landscape plants and lawns. We may immediately jump to the conclusion that a pest caused the problem. Amazingly, most problems are not caused by an insect or critter. Most are caused by stress factors such as too much or too little water, too much or too little sun, soil problems, other environmental challenges, or maintenance practices.
Often the lack of winter watering causes plant problems at this time of year, but that’s certainly not the case this year. It might instead be saturated or soggy soils that damaged plant roots and are making plants look sick.
Environmentally aware gardeners try to accomplish long-term pest prevention and reduction with minimal pesticide inputs. We use integrated pest management techniques to reduce pests and their damage through a combination of strategies including biological control, habitat manipulation, cultural practices and planting resistant varieties. Pesticides are only used after monitoring shows that the pest population density warrants it.
Before applying pesticides such as herbicides (weed killers), insecticides, fungicides, or rodenticides, identify the cause of the actual problem. To tell if an insect is the cause look for live insects and then get them identified so you can know if they are detrimental or beneficial.
If you don’t find live insects, you may see their remains: eggshells, mummies, cocoons, or possibly webbing on stems that may indicate a caterpillar or mite issue. You might find scale or aphids by spotting their protective waxy coverings or the sticky residue they leave behind called honeydew. Borers or bark beetles may produce sawdust, wood chips or pitch balls on trunks or trees or at their base. https://extension.unr.edu/publication.aspx?PubID=2811
To manage insects effectively usually takes one or more integrated pest management (IPM) strategies. Applying IPM techniques, insect control can be split into five separate categories.
The first is prevention and involves buying, installing, and using pest-free plants, soils, and other materials. Prevention covers removing insects before eggs are laid. This requires regular inspection and monitoring of plants.
Good cultural practices include proper planting and timing of planting, efficient but not excessive fertilization, appropriate timing and amount of irrigation, rotating crops, and good sanitation to name a few.
Handpicking pest (whether insects or weeds), putting up barriers such as row covers or using sticky traps are all mechanical or physical techniques to manage pests. Using living predator or parasitic organisms can biologically reduce pest populations. Finally, chemical options are the last resort. https://extension.unr.edu/publication.aspx?PubID=2661
JoAnne Skelly is Associate Professor & Extension Educator Emerita at University of Nevada Cooperative Extension. Email skellyj@unr.edu.