Mitigate Mites

TOP: Phytoseiulus persimilis feeding on a spider mite. P. persimillis can be released every 7-14 days. BOTTOM: Two-spotted spider mite infestation on rose.

Two-spotted spider mites, unfortunately, are alive and well and tough to control. There are many products containing different active ingredients which are effective on mites, but the simple truth is, there is no “silver bullet” for mite control.

Control is vital because of the damage mites cause to plants. Mites are often listed in the top five most serious arthropod pests of ornamental production. There is a pest mite for almost every part of the plant –flower, bud, leaf, root and bulb. Mite populations can easily reach damaging levels in crops if a proper management strategy is not in place year after year. In order to fight resistance and maintain mite control, an integrated crop management (ICM) program is imperative.

ICM Strategy
Today’s growers are under increasing pressure to produce crops economically and sustainably. Growers should consider all aspects of production with an ICM approach. For mite control, biological control agents should be integrated with physical and chemical controls to create an overall management system. Compatibility between biological control agents and other plant protection products has to be carefully planned according to each grower or nursery’s problematic pests, cropping systems and rotations.

Miticides/insecticides with the active ingredient abamectin work well in an ICM program with biological controls. This material controls mites (two-spotted spider mite, cyclamen mites, broad mites) and leafminers, and it has an expanded label to include suppression of aphids, thrips and whiteflies on ornamental plants. The ICM program below can serve as a general guideline for a mite control program.

ICM Tips
The following are tips to keep in mind when using multiple plant protection products in an ICM program.

• Rotating products with different active ingredients is necessary to avoid resistance and achieve control. This includes the use of beneficials to help reduce resistance development.
• Include at least three different modes of action in rotation. Apply each product two-to-three times back-to-back. Follow label recommendations for application intervals.
• Avoid overuse of a single miticide.
• Ensure spray coverage reaches top and bottom of leaves and stems. If there are problems getting control with every miticide used, there is a good chance that spray coverage is insufficient.
• Use surfactants with most miticides on thick or waxy foliage according to label recommendations.
• Use systemic or translaminar products with a surfactant according to label recommendations.
• Application timing depends on mite pressure and time of year. Under heavy pressure, apply every 7-10 days. The first spray application should target the mobile stages (adults/immatures). The second spray application should target the immature stage and eggs.
• Scouting must continue after your pesticide application in order to ensure that your management practices are successful.

Click picture above to see the full ICM Program for Mites

Successful Mite Scouting
Check the undersides of leaves using a hand lens to detect spider mite infestations before they reach damaging levels. Frequent and careful inspection of plants is necessary because, by the time plant symptoms are obvious (silvery speckling/stippling of the upper leaf surface), control will be difficult and potentially expensive. Mite feeding can cause a multitude of symptoms, such as leaf cupping, discoloration, distortion, spotting, speckling and stunting, stem russeting and discoloration, as well as distorted and discolored flowers. Damage due to mites can resemble that from other causes. For example, symptoms can look similar to insect feeding, nutritional deficiencies, physiological stress, herbicide damage, etc.

In the end, mite control is all about prevention. Use these guidelines and practice ICM before mites and other pests or diseases become a problem.

Marla Faver is a technical services representative for Syngenta Plant Protection.