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Show Some Potato Insects of Utah' By GEORGE F. KNOWLTON2 Grasshoppers of several species often have been responsible for serious defoliation of potato plants during seasons of heavy infestation. Control. Use a poison bait consisting of: Bran without shorts (or alfalfa meal) 25 pounds; mixed dry with white arsenic, crude arsenic, or Paris green, 1 pound, cheap molasses 2 quarts mixed with 2 gallons of water. (One pound of sodium arsenite may be substituted for the white arsenic, this being mixed with the water and syrup rather than with the dry bran). Thoroughly mix the liquid with the bran and poison; add sufficient additional water to make the mixture "ball" in the hand (not too wet). Scatter the bait broadcast in early morning of warm days, where grasshoppers are abundant. Use control measures before the young grasshoppers become adult and scatter from their hatching areas. Jerusalem cricket, Stenopelmatus lonqispina Brunner, is com mon in many parts of Utah, and occasionally has been observed to feed upon potato tubers. This injury appears to be of rather rare occurrence in Utah. Thrips of several species, including Frankliniella occidentalis (Pergande) and F. tritici (Fitch), attack the flowers and leaves of potatoes throughout Utah, causing moderate injury during most seasons. The leafhopper, Empoasca [ilamento DeL., causes noticeable spotting and sometimes severe injury to potato foliage Several other leaf every season. hoppers occur in smaller numbers upon potato plants, including Acerataqallia sanguinolenta (;Prov.); the beet leafhopper, Euiettix tenellus (Baker), which was found to be breeding upon potato plants at Moab during August of 1935; occasionally Thamnotettix montanus Van D., and Cicadula sexnotaia (Fallen). The treehoppers, Cereso: bubalus (Fabr.), C. basalis Walk, C. gllettei Van D, and occasionally others have, upon various occasions, been found to occur upon potato plants in moderate numbers. The potato Paratrioea cockerelli (Sulc), has at various times caused extensive psyllid, and severe damage to the potato crop in many parts of Utah. Most frequent injury seems to occur in certain southern portions of the state. Equally severe injury occurs in northern Utah during outbreak years. The feeding of large numbers of scale like P. cockerelli numphs upon potato foliage results in the production of a condition commonly called "psyllid yellows,,' described by Richards in 1928 (Phytopath. 18: 140). ControL-Thoroughly spray potato plants with commercial liquid lime sulphur, 1 gallon to 40 gallons of water (or equivalent amount of home-mixed or dry lime sulphur) as soon as nymphs become abundant. Much injury is avoided if control measures are applied before noticeable injury occurs. The green peach aphid, Myzus persicae (Sulzer), and the potato aphid, Macrosiphum solani/olii (Ashmead), occasionally be come abundant enough to cause injury. The aphids, Myzus pseudosolani Theo bald and M. circwmflesus (Buckton) also have been taken from potato foliage in Utah, together with winged "accidentals" of several additional species. Mosaic, rugose mosaic, spindling tuber, leaf roll, crinkle mosaic, leaf-rolling mosaic, yellow dwarf, and other diseases of potatoes are transmitted by one Contribution from the Entomology Department, Utah Agricultural tton. Experiment Sta 2 Associate Entomologist. Authorized by Director, Oct. 15, 1936. 151 |
