The Hessian Fly

Prof A. G. Cook of the Agricultura College, under date of April 30, writes to the I'oH and Trïtntn concerning tha scourge, the Hessian fiy, and proposing prompt and heroic treatinent, as follow Aa this is to be eminontly a practica article, I hasten over the facts that tbi is an iuiported insect, coming witl those other pests, the hireling Hessiau of General Howe's aruiy ; that it spreac over the country from New York City as a center ; that then, as now, it was a grievous ill tor a time, and then suemec to disappear, though a rtmmant re mained, and sufficient lo agnin stock tho country when the conditions made its struggle for life and prosperity leu aevere ; that now it has come again to blust the hopos of the most necessar; and useful class of society. I slin.ll alsü hare to forbear a descrip tion of the habita and special ohm-acte; of the fall brood - there are two brood of the insects each year - as that is no now a subject of inmediato iniportance PRESENT CONDITION. Ever since the MHh inst. the spring flies have been hatchingor coming froiu their pupal homes. They are very un merous, fairly Bwarming in many of the wheat fields and, by careful dissection under the compound microscope, I have actually counted over two hundred (200 eggs in a single fly. Henee we can faintly comprehend the stupendous magnitude of the evil - especially as two or three larvte, which can hatcb from as many eggs, will ruin a stock o: wheat. 1 regret to say that it is difficult to fiud a singla one of the three or tour leavos of each stook that has nol from three to thirty eggs along the grooves which line it inside. Henee we see thedanger is imminent I think indeed that it would be as safe to count on good legislation from the present Congress as on the present wheat erop, where the flies are so numerous. 13 THEKE ANY HOPE. Un careful exainination we find a little black tour winged parasite, hardly halt' as large as the Hessian fly busily engaged in laying its eggs in the eggs of the fly. Of oourse each egg that receives oue of these parasitic eggs re ceives its speedy death warrant. But there are not one of these to twenty of the Hessian flies, in the fields about here, and by timing each I fitid that while the Hessian fly is but a quarter of a minute laying one of her egurs, the parasite is three-fourths of a minute. Again, the parasite has to crawl about the leaf, feeling with her antennae to find each succossive nidus for her eggs, while the Hessian fly pushes out her yellow jointed, spy-glass-like oviposition, lays down au egg, and flies off in a trice to a new leaf to repeat the ruinous work. So here I think we cannot look for exemption by the parasites the prosent season. WHAT, TUEN, 8HALL BE DONE? In case the flies are swarming upon your fields, I should advise feeding or cutting the wheat close down to tho jrouud, to be commencod at least as soon as the latter part of this week or the first of nexl. By feeding we save tho wheat stocks and leaves that are cropped off, while Dy cuttiug with a scytbe or inower, the work would be more universally per'ormed, and the ground lesa tramped and cut up. Of course sheep would inure the ground luss thau cattle. But this feeding aud cutting il not lesirable, unless tho Hessiau fly danger hreatens. W1IAT SUALL GUIDE U3 'i 1. If the wheat in the fields looked quite dead and injured the last part of November, 1877, then you may be pretty mui' that an evil day is at hand. Snc.Ii ack of vigor could only have come froui ,he ravages of the fall brood of the fly ; and when thero was a fall brood, there will very likely be an equally nunierous spring brood, aud the feeding or cutting will be opportune. 2. Go into your fields any of these warm daya, even after a heavy rain, if rou will wait an huur for tho flies to dry off, recline on the ground, and, if you see hosts of small, black flies, looking very like a half-grown mosquito, very )usy at their work - closer observation will even detect the extensión of the ittle red ogg - then youmay know that a wheat erop this year eau only be obained by prompt aotion. Thttt you may be more certain, I will tate that the female has a red abdomen, jofore sho has laid her eggs, so she will ook like a mosquito that has drawn her 111 from our blood. The orange yellow py-glasa-like ovipositor will algo be notod terminating the shortor darkor males ; the claspers, looking like a pair of nippers, will be seen. f'M. Yery cIosh scrutiny will detect the minute red oblong eggs, fastened in the grooves or oreases ot' the leaves on the side facing the stuik. My littlo boy, lesss tlniii üv years ot' age, can iind these without trouble. lf these are nuuierous, then again I aay feed oft' or cut off. Of oourse, tho fnrosity, a small, active black fly, may in some seotiong be as numerous as flieti and stay the damages.