Broad Mite: The “Sneaky” Mite* Raymond A. Cloyd Kansas State University, Manhattan, KS and Karen K. Rane Purdue University, West Lafayette, IN         Have you ever experienced problems with certain plants that appear to be associated with either thrips or spider mites? Have you then made an application of a pest control material such as spinosad (Conserve) or a miticide, and yet the problem seems to be getting worse? Well, we encountered a situation with English ivy, Hedera helix and impatiens, Impatiens walleriana in which a greenhouse grower had plants that were displaying symptoms typical of thrips feeding injury. For example, on impatiens, the leaves were curled downward, and the new growth was distorted and there was a loss of variegation on the English ivy (Figure 1 ). Upon further investigation, we determined that the culprit was actually broad mite. Since broad mite is not visible to the naked eye, and even difficult to observe with a 10x hand-lens, it is not uncommon to associate broad mite damage with another arthropod pest of greenhouses. In addition, broad mite injury may resemble a nutritional imbalance, environmental issue (too cold or hot), or even a virus.         Broad mite (Polyphagotarsonemus latus) is a pest of a wide-range of greenhouse-grown crops such as begonia, cyclamen, fuchsia, Transvaal daisy, English ivy, and New Guinea impatiens. Broad mite requires very different environmental conditions than twospotted spider mite (Tetranychus urticae). This mite tends to be a problem under cool temperatures (around 15ºC or 59ºF) and high relative humidities (70 to 80%), which are conducive for development and reproduction. Broad mite feeds on young foliage and floral parts such as flower buds retarding growth and preventing flowers from fully-developing. Typical symptoms of feeding by broad mite include bronzing and distortion of plant leaves. Excessive populations often lead to broad mite feeding on both the upper and lower portions of the entire leaf surface. The presence of broad mite is typically after plant injury is noticeable as opposed to actually finding the mites themselves.         Broad mite adults are approximately 0.25 mm long, amber to dark-green in color, and oval in shape with a white strip extending down the back. Eggs are oval-shaped and covered with bumps (Figure 2 ). Broad mite tends to feed on the underside of young leaves. The life cycle from egg to adult takes less than one week to complete with females capable of laying up to 25 eggs. Broad mite populations may disperse within a greenhouse by attaching themselves to whiteflies, including the greenhouse (Trialeurodes vaporariorum) and sweet potato (Bemisia tabaci) whitefly         There are a number of pest control materials with miticidal activity that are registered for control of broad mite including abamectin (Avid), bifenthrin (Talstar), chlorfenapyr (Pylon), pyridaben (Sanmite), and spiromesifen (Judo). Those products with translaminar activity such as Avid, Pylon, and Judo are likely to control broad mite since the mite is normally protected from contact miticides. Preventative applications are required because once damage is evident it may be too late to control broad mite. Removing plants that are exhibiting symptoms, and those surrounding symptomatic plants, is essential in order to prevent the spread of broad mite onto other plants. The predatory mite, Neoseiulus barkeri may be used to control broad mite in greenhouses.         Broad mite will continue to be a problem in greenhouses although populations may fluctuate depending on the plant species, plant age, plant quality, and environmental conditions. Currently, there are few miticides available for broad mite although more miticides are including this mite on the label; however, efficacy data is minimal or lacking. In addition, globalization or the movement of plants from off-shore growing facilities in other regions of the world such as South America may contribute to the potential of introducing broad mite or even cyclamen mite into greenhouses. * Mentioning of products in this article does not mean endorsement, nor lack of mention to other products implies a criticism. Always conduct a small test before applying any product to your crop.