337 



trees of both orchards and the application repeated the next day. From Mr. Mur- 

 rell's observations it would appear that a great number of the beetles were killed 

 (or perhaps only temporarily disabled f) thereby, but at any rate there was no dimi- 

 nution of the invasion. Then Mr. Murrell sprayed the trees of the first orchard 

 with London purple water (2 oz. to 40 gallons of water) and repeated the spraying 

 the next day, using a Nixon spray machine and a Japy knapsack sprayer which had 

 been furnished by the Virginia Agricultural Experiment Station. Mr. Murrell was 

 not certain whether or not any beetles were killed by this spraying; at any rate, the 

 evil did not abate. On April 14 Mr. Murrell changed his tactics and commenced 

 spraying with kerosene emulsion. The emulsion (milk and kerosene) was correctly 

 j and successfully made, diluted four times its volume with water, and applied to the 

 I trees by means of the Nixon pump, three men being necessary to carry on the oper- 

 I ation. I witnessed myself the spraying, which was a very thorough one, and which 

 i progressed at a rapid rate wliere the ground was even. Most of the beetles jumped 

 off the trees the moment they were touched by the liquid, and only a few (especially 

 t those hidden Avithiu the dead buds) were caught and enveloped by the emulsion on 

 j the trees. These latter specimens did not recover and died; of those that had 

 I jumped to the ground I collected a small number in a tin box and found them all 

 I dead a few hours afterwards. It may be assumed, therefore, that most specimens 

 that had been touched by the emulsion were killed. In the early morning hours of 

 ! April 15 there was a heavy rain shower, and an examination of the trees treated the 

 day before with the emulsion showed the presence of a small number of beetles. On 

 1 the wet ground, however, many apparently healthy beetles were slowly moving 

 i about, apparently waiting to get dry before attacking the trees. 

 I The invasion of Crepidodera rufipes has plainly a strong resemblance to that of the 

 'i well-known Macrodactylus ; in both cases thousands of newly-arrived specimens re- 

 place those that have l)een killed by the application of arsenical poisons or pyre- 

 ] thrum or kerosene emulsion. In the case of the Grei)idodera the arsenical poisons 

 evidently have very little or no effect whatever, since the young trees are mere 

 naked slender shoots, without branches or leaves and with smooth bark. In short, 

 the old method of jarring the beetles down is here plainly more eff"ective, cheaper, 

 and more time-saving than the other remedies just mentioned. To test this method 

 I rigged up my " insect umbrella" (consisting of a piece of common cotton cloth one 

 yard square and kejit stretched out by means of two sticks). It was found that a very 

 slight knock with a thin stick is sufficient to dislodge the beetles from the trees, ex- 

 cepting the specimens hidden within the dead buds. A stronger knock with the 

 stick is liable to jar the beetles either in the wrong (opposite) direction or beyond 

 the circumference of the ch)th. It was further found that, if little judgment is 

 exercised as to the most favorable side where to apply the jar and how and where to 

 hold the cloth, all or nearly all the beetles can be knocked down onto the cloth ; in 

 other words, the beetles do not jump off', but simply fall down, following the impetus 

 given by the shock. I convinced myself of this fact by counting in several in- 

 stances first the beetles on the tree and then, after jarring, the beetles on the cloth. 

 Finally, it was found that this operation can be proceeded with almost as rapidly as 

 a man can walk, and I estimated that a single man could easily attend at least two 

 hundred trees within one hour. 



This remedy will be only effective, however, if the jarring is repeated as often as 

 possible — say at least twice each day as long as the invasion lasts. A more handy 

 contrivance than the somewhat clumsy insect umbrella could be easily and cheaply 

 constructed, and from former experience I know that an old parasol which is lined 

 on the inside with heavy cotton cloth does excellent service. 



As a mode of prevention, Mr. Murrell suggested to inclose the upper part of the 

 trees within gauze bags. If these bags are properly tied to the stem, they will no 

 doubt protect the trees ; but the great expense will no doubt prevent their use on a 

 large scale. In order to be effective, these bags must be at least one foot long and of 



