What Sprays Can Be Used for Highbush Blueberries

Iron Chelate

• Highbush blueberry plants often suffer from iron chlorosis, a condition that causes leaves to grow paler in green color and stunted in size. The Ministry of Ontario, Canada, recommends testing the soil every year or two to determine the level of iron in the soil available for the plants. Iron deficiency can occur when the soil pH is too high. Raking sulfur into the soil helps lower the pH. For fast correction of low iron levels, a foliar spray of iron chelate is recommended to bring temporary relief to the plants.

Fenbuconazole

• A number of fungus conditions can trouble blueberries, including Septoria and leaf spot. Sprays are often used to control these fungi, but environmental agencies have banned the use of some of these because of their impact on health and the environment. According to the University of Florida, febuconazole is a fungicide approved for use to control leaf spot on blueberries.

Dormant Oil

• Highbush blueberries sometimes become infested with scale, a hard-shelled insect that infests the bark of blueberry plants. Scales take on the color of bark and may be hard to detect without the aid of a hand lens. The University of Connecticut recommends the use of a dormant spray like Superior oil to control scale on blueberry plants, thoroughly covering all leaves and stems. Do not use the oil spray when temperatures are below 32 degrees F.

Spinosad

• Flower thrips can infest both highbush and rabbiteye blueberry plants, feeding on the pollen, ovaries, petals and berries. Spinosad is a good choice for thrip control because of its minimal effect on beneficial insects in the environment, according to the Florida Blueberry Growers. This is important to blueberries, as they depend on insects to help pollinate the plants.

• Integrated Pest Management recommends using carbaryl as a pre-harvest spray to control Japanese beetles on blueberries. Applied to the plants one to two times per season, carbaryl also controls fruitworms and blueberry maggot flies.