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What to Use to Kill Grasshoppers on Plants

By Nina Rotz ; Updated July 21, 2017

Grasshoppers pose a significant hazard to garden plants including vegetables flowers, and other leafy greenery. However, killing grasshoppers can pose a significant challenge, and many remedies that work on other common garden pests prove ineffective when used against grasshoppers. Learning which remedies do work and how to use them can be important to keeping these nuisance insects from destroying a prized garden.

Insecticides

Several types of insecticides exist that are effective against grasshoppers. These include chemical insecticides as well as specially formulated fungal insecticides that target grasshoppers specifically. Among the more effective solutions are those containing carbaryl, acephate, permethrin and deltamethrin. Carbaryl is the only insecticide among these that is used as bait to control grasshopper populations. Gardeners should be sure when choosing insecticides to use ones appropriate for the type of plants they are protecting. Insecticides for ornamental plants may differ from those for vegetable gardens.

When to Apply Insecticide

Many gardeners make the mistake of not using an insecticide to control grasshoppers until adult grasshoppers appear. Unfortunately, insecticides are most effective against newly hatched juveniles, and they are rarely effective against adults. This means that gardeners get best results using insecticide during the earlier months of the growing season – mid to late June in most areas. When applying insecticides, it is important to target the source of the infestation if possible. Surrounding grassland and ditches are common areas of grasshopper egg laying and growth.

Organic Repellents

In addition to chemical insecticides, there are many organic repellents that you can make at home for grasshopper control. Among the more effective solutions are pungent herbs such as garlic. Simply make a solution with crushed garlic cloves and spray it on plants. However, do bear in mind that this does not kill grasshoppers and is only one of the measures that should be used to protect gardens from these pests.

Natural Predators

Grasshoppers have numerous natural predators. Those who prefer to use insects to fight insect pests can purchase praying mantises for their garden. Larger mantises feed off of grasshoppers and other smaller insects. Those who have the option to do so may also consider having chickens to control their grasshopper populations. Chickens drive down grasshopper populations in large numbers. However, natural predators may often be outmatched in years of particularly strong grasshopper outbreaks.