. Bulletin. Insects; Insect pests; Entomology; Insects; Insect pests; Entomology. Fig. 2 The grape leafhopper : Nymph of the first molt. (iroatly enlarged. (Origi- nal.) SPKAYING AGAINST THE GRAPE LEAFHOPPER. 3 â warm afternoons of early autumn the air will be filled with thousands of these little creatures drifting somewhat aimlessly on the light breeze and causing considerable anno^^ance by get- ting into the eyes, ears, and mouth of the beholder. A close observation of the underside of the leaves of grapevines at this season is likely to reveal the immature or nymphal stage of the insect (f
. Bulletin. Insects; Insect pests; Entomology; Insects; Insect pests; Entomology. Fig. 2 The grape leafhopper : Nymph of the first molt. (iroatly enlarged. (Origi- nal.) SPKAYING AGAINST THE GRAPE LEAFHOPPER. 3 â warm afternoons of early autumn the air will be filled with thousands of these little creatures drifting somewhat aimlessly on the light breeze and causing considerable anno^^ance by get- ting into the eyes, ears, and mouth of the beholder. A close observation of the underside of the leaves of grapevines at this season is likely to reveal the immature or nymphal stage of the insect (fig. 2). These vary greatly in size, from those just hatched to the full-gTown nymphs with well-develoj)ed wing- pads (fig. 3), but they have alwaj^s the same general form. These leaf hoppers belong to the same order of insects as do the scale insects and the plant-lice and secure, their food by sucking the juices from the plant in much the same manner as the mosquito sucks blood from an animal. A knowledge of this method of taking food is of the great- est importance from an economic standpoint, since insects which take their food in this way are usually amenable to a spray application of an entirely different quality from that which is used in the case of insects Avhich chew or masticate their food. Sucking insects are usually combated by the use of some caustic or smothering substance which must come in direct contact with the outside of the body of each individual, practically at the time of aiDplication and in sufficient quantity and strength to effect its almost immediate de- struction; whereas, in the case of the chew- ing insect a stomach poison must be applied, not to the body of the insect, but to the sur- face of that portion of the plant or fruit upon which the insect feeds. The adults and the nymphs of the grape leafliopper feed upon the underside of the grape leaf and by sucking the juices there- from cause it to take on a yellowish, mottled appearance (fig. 4), w
Size: 1334px × 1874px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, booksubje, booksubjectentomology
