Two - spotted spider touch ( Tetranychus urticae ) have been observe recently , especially on plants in hanging baskets hang high in hot wry areas in the nursery . Two - spotted wanderer mites ( TSSM ) are a major pest of many greenhouse harvest . They feed primarily on the undersides of leafage where they pierce the cells with their stylet - like mouthpart and fellate out the contentedness . The feeding combat injury outcome in a lightheaded chlorosis or stippling on upper foliage surfaces . The destruction of cells results in reduced photosynthesis and , as damage increases , whole leave turn yellowed . Leaves may drop and finally lead to death of the plant . In severe infestations , plant may be covered with webbing , which is why they are referred to as spider mite .
by Geoffrey Njue , Extension Educator , UMass Extension ’s Greenhouse Crops & Floriculture Program
Look on leaf undersides for the mites and their egg . Magnification , such as a manus lens , is take to see them . TSSM are small and have eight legs . Adult female person are about 0.5 mm long and have an oval body that is rounded at the rear death . male person are slightly smaller with a body that is narrow and more pointed at the rearward end . The people of color can deviate from orange , to light jaundiced , to yellow - brown , to dark - green , with two dark spots on both sides of the body . TSSM lays more eggs and develop faster at high temperature and lower humidness . Development starts around 54º F , increase with temperature , starts to refuse after 86º F and stop consonant at 104º F. TSSM can be a problem during dry and hot weather condition conditions . Water - stressed plant are more susceptible to spider mites .
Biological managementThe most efficacious biological control agent for TSSM is the predatory mite Phytoseiulus persimilis . P. persimilis feeds only on two - spotted spider mites and feed on all life stages , but has druthers for bollock . Phytoseiulus persimilis develops faster than TSSM , as long as temperature are not too eminent . At 68 ° atomic number 9 the average generation prison term of P. persimilis is shorter than that of the mites . Under ironic warmer conditions P. persimilis has difficulty keeping up . The predatory touch Neoseiulus ( Amblyseius ) californicus is more tolerant of high temperature and lower humidness . big concentrations of TSSM ( hotspots ) can also be controlled using gall midge Feltiella acarisuga . The larva of Feltiella feast on all stages of two - tell apart spider mites .
Chemical managementFor chemical direction of TSSM , contact or translaminar miticides can be used . Translaminar miticides are more effective because they penetrate foliage tissue and take shape a reservoir of active ingredient within the leafage which provides extended residual activity . treatment require good coverage to the undersides of the leaf and may need repetition applications during affectionate weather . Miticides with translaminar activity include abamectin ( Avid , Lucid , Minx2 ) , abamectin & bifenazate ( Sirocco ) , chlorfenapyr ( Pylon ) , and spiromesifen ( Savate ) . inter-group communication miticides include fenpyroximate ( Akari ) , bifenazate ( Floramite SC , Actaute SC ) , hexythiazox ( Hexygon , Hexcel 50 DF ) , Clofentazine ( Ovation ) , and pyridaben ( Sanmite ) .
Do not employ Savate on New Guinea impatiens or geranium . Always read pesticide labels for plant safety information and verify to stick to all recording label recommendations and restriction . Also be sure to turn out across different modes of action ( MOAs ) to forbid impedance development in the pest population .
For more information on TSSM refer to the following links :
author : University of Massachusetts Amherst
