Insecticide For Lemon Tree

Lemon trees (Citrus limon) produce edible fruit and fragrant flowers in U.S. Department of Agriculture plant hardiness zones 9 through 11. This broadleaf evergreen is susceptible to various problems such as insect infestation and fungal disease. When these pests attack the lemon tree, applying certain sprays will help control the problem and protect the fruit.

Oil Spray

1. Neem oil and horticultural oil are two pesticides that will control both insects and fungal diseases. Neem oil is plant-based, created from the neem tree, while horticultural oil is mineral-based, typically containing refined petroleum. At one time, horticultural oils were only used as a dormant spray since their heavier nature would damage leaf buds. Horticultural oils can now be applied anytime during the season. Oil sprays control sap-sucking garden pests, powdery mildew and greasy spot. Oil sprays can damage lemon trees if applied at temperatures above 90 degrees Fahrenheit, and multiple applications may be necessary to completely rid the lemon tree of the pest.

Insecticidal Soap

1. Insecticidal soap controls various species of garden pests including scales, aphids and mealybugs. This all-purpose pesticide breaks down rather quickly and won’t leave residual chemicals behind. Once the pesticide dries on the plant, it is no longer effective. Since it controls aphids — which transmit the damaging Citrus tristeza virus from one plant to another — insecticidal soap plays a vital role in keeping viruses at bay. Insecticidal soaps are most effective against soft-body pests insects such as thrips and mites.

Copper Fungicide

1. Copper fungicide has long been used to control various bacteria and fungi infecting plants such as lemon trees. It interferes with the fungal pathogen’s enzyme system and disrupts the spores’ germination process. It controls scab, botrytis diseases, anthracnose, citrus blast and septoria spot. Copper fungicides are safe to use on the lemon tree up to 24 hours before harvest. Typically, copper fungicide isn’t harmful to birds or bees but is highly toxic to fish and other organisms. Repeated uses of copper fungicide will cause a buildup in the soil.

Bacterium Insecticide

1. Bacillus thuringiensis is ideal for targeting certain lemon pests such as the larvae of butterflies and moths. This includes leaf-eating caterpillars, bagworms, hornworms, tent caterpillars, leaf rollers, loopers and webworm. Bacillus thuringiensis is a naturally occurring bacterium that acts as a stomach poison that prevents the larvae from eating. The larvae will starve and die in two to four days. Each strain of Bacillus thuringiensis targets specific pests. For example, kurstaki targets the larval stages of moths and butterflies, and israelensis controls fungus gnat and mosquito larvae. Bacillus thuringiensis is nontoxic to humans, mammals, bees, birds, fish and other beneficial insects.