115 
as well as the short-winged form (Fig. 27, a )—were found 
abundant in one greenhouse at a date which would preclude any 
possibility of their having developed out-of-doors that spring; and 
they did not develop inside the greenhouses from eggs deposited 
the fall before, as the houses had been examined during the winter 
and not an active “hopper" found. It was also observed that the 
individuals became adult in the fall, as cold weather set in. From 
these observations it appears that the adults hibernate in green¬ 
houses or out-of-doors and become active in the spring, when 
they deposit eggs for that season's generation—instead of doing 
it in the fall before, as has heretofore been supposed. 
methods oe control 
Clean culture around greenhouses, to destroy the breeding places 
of the leaf-hopper, is perhaps more effective against it than a spray 
mixture indoors. Late in fall all vegetation in the immediate vicin¬ 
ity of the greenhouse should be cut down, and as an additional 
safeguard it is desirable that the land be cultivated at once. Such 
procedure is desirable during the spring and summer also, not only 
for the reason already assigned, but also as a defense against in¬ 
festation from adjoining fields. One year's practice of this radical 
measure is worth many years of half-way methods, and if the work 
is thoroly done the danger of reinfestation is very slight. 
If, however, the insect appears in the greenhouse before the 
florist has taken preventive measures, or in spite of them, he should 
at once use a contact insecticide, such as kerosene emulsion or one 
of the nicotine extracts. Because of their leaping habit it is some¬ 
times a difficult problem to hit the insects, but with sufficient care 
and thoroness spraying will prove of value. Kerosene emulsion is 
made as follows, the formula being for a 66 percent stock solution. 
Soap* . V2 pound 
Kerosene. 2 gallons 
Water. 1 gallon 
If the soap is hard, cut it into fine shavings and dissolve in boiling 
water, after which remove the vessel from the fire, add the kero¬ 
sene immediately, and mix thoroly. The mixing may be best and 
easiest done by churning for about ten minutes with a force-pump, 
the nozzle being turned back into the liquid. When thoroly emul¬ 
sified it will have the consistency of thick cream, and the oil will 
not separate out. For a 10 percent emulsion, dilute this stock so¬ 
lution with 17 gallons of water. Soft water is best, both for the 
*Either hard or soft soap may be used. Whale-oil soap and “Tak-a-nap” 
soap have given excellent results. 
