The Potato Leaf-Hopper and Tarnished Plant Bug in 1916

S. Marcovitch
1921 Journal of Economic Entomology  
Ball records in this JOl'Rl\'AL a severe epidemic of the potato leafhopper on potatoes in Vi'isconsinfor the summer of 1918. In a series of~plendid experiments he also proves that the causative agent is the potato leaf-hopper, Empoasca mali Le B., and not the so called tipburn. The writer had reached the same conclusion during the summer of Hl1fi whm connected with the l\'linnesota Experiment Station. The results "'ere published in the Princeton Union August 24, 1916, describing "havoc in the
more » ... ing "havoc in the potato fields," in the vicinity of Princeton. Minnesota. Ir. Saxon a potato farmer in Princeton, called our attention to the hoppers. It was only his insistence that the bugs were the cause of the damage, that caused more accurate observations to be made. As far back as IfnI. l\lr. Saxon reports that he noticed the leaf-hoppers injuring his potatoes, causing as much as 35 per cent. damage. Several weeks in the field "'ere devoted to studying and experimenting with hopperdozers and spraying. In ::>'linnesota,the Triumph variety suffered most severely. The leaves were dYIng so rapidly that a perceptible decaying odor could be smelled. From 350 to 500 leaf-hoppers and about 50 tarnished plant bugs were counted on a single vine. In addition to the regular potato leaf-hopper, Empoasca malt', there were also present in some numbers two other leaf-hoppers, Deltocepha!us hlimicus and Ct'cadula 6-notata as well as a large brown Drosophila, probably attracted by the decaying odor. It was noted that the leaf-hoppers suck on the small veins causing the leaf to curl along the margin while the tarnished plant bugs suck on the midrib or the tip of the gmwing shoot causing the leaf to curl upwards or the shoot to wilt entirely. If the stem of a shoot that has been stung by the tarnished plant bug is cut open, it will be found to be rotten. Very often a distinct swelling can be noted on the stems. Later varieties, such as the Burbank, did not suffer badly probably because they are not so tender as the Triumph, or as Ball observed that not enough foliage is present for egg deposition of the spring brood. During the early part of September wet rainy weather set in. The leaf-hoppers promptly disapppeared and many were noticed clinging to leaves, having been attacked by a fungus. Observations were made on early Ohios in the western part of the state in the vicinity of Moorhead. No burning was found and but very few leaf-hoppers were noticed. The season was wet there and this probably accounts for their absence. The work in regard to the control consisted in running a hopperdozer over 20 acres of potatoes. Both kerosene and tanglefoot were by guest on June 6, 2016
doi:10.1093/jee/14.1.61 fatcat:fv7oqawhsjecdimn6rclopoanu