110 TRANSACTIONS OF THE ZLLLNOIS 



lowing morning my catcli of insects greatly exceeded in numbers all tliat had been 

 previously taken in the twenty or more days' run with our curculio catcher. 



From the time of this great increase until past the middle of the month, after each 

 warm day, great numbers of curculios were captured, the numbers taken always 

 being greatest after the wind had been blowing from my grounds to orchards distant 

 one, two and more miles, and from which the fruit had but recently fallen. 



From this circumstance was deduced the following fact, if fact it be : that curculios, 

 as well as some other insects, discover their food by scent, and by flying against the 

 wind they reach the spot where it is to be found . 



It would be a difficult task to determine the exact ratio of increase of the curcuho. 

 The casualties to which they are Uable are various. And yet from observation it may 

 be stated, as a general rule, that just in proportion as we provide a regular and 

 increased supply of food for them, as by the multiplication of fruit, just in that ratio 

 wiU be the ratio of their increase. In many neighborhoods in the "West, where the 

 growing of fruit is the chief occupation of the inhabitants, there the curculio has 

 already become master of the orchards, a few days only in the early season being 

 required by them in which to render worthless the fairest prospect of the largest 

 orchards, or those of whole disti'icts. It has been my fortune during the past few 

 years to visit many orchards producing their first and second crops . As a rule , in 

 nearly all of these that were fruiting the Ihst time, a few only of the fruits were stung; 

 especially was this true of orchards that were a considerable distance from trees that 

 had matured several crops. But when old fruit districts which are badly ovemin by 

 curculios become fruitless, either by cold or by the early destruction of the fiTiit by 

 insect enemies, then the curculios migrate in such numbers and to [such distances as to 

 sweep whole orchards miles away. If not, how else are we to account for the wide- 

 spread destruction of fruit in the new iruit districts nearest the old, in which there 

 was a failure of fruit ? 



It may be stated as a general thing that when curculios once enter an orchard, they 

 will in the second or third year at farthest so increase as not only to sting aU the fruits, 

 but, on the majority of them they will make from ten, to forty, or more cuts. One 

 egg in each fruit would have made it sufficiently worthless, either for market or for 

 food. Indeed so certain is the ratio of increase of curculios in orchards once invaded 

 by them in which there is a yearly supply of fruit, that it is only necessary to under- 

 stand the conditions of orchards, with reference to stung fruit one year, to enable one 

 to predict, with much correctness, with reference to the following year, of the com- 

 paritive scarcity or plentifulness of the curculio. In neighborhoods infested by cur- 

 culios, where contiguous orchards in considerable numbers occur, there no general sue- 

 cess need again he looTced for, until a scarcity of fruit shall reduce (he curculio, or until the 

 proprietors of orchards shall all unite to destroy them. 



In districts where fruit orchards are near to each other it will often prove of no avail 

 for one orchardist to daily catch and destroy the c '■i:ulios in his owa. grounds while 

 those of his neighbors are neglected. The reason of this wiU be best understood when 

 we state, that at a temperature of 70" and under, curculios are unable to fly, and are 

 comparatively inactive at a temperature of 80° . Hence at 80° and under they may be 

 easily jarred down upon sheets, but so soon as the temperature reaches, say 85° and 

 upwards, then the curculio flies with so much freedom especially if the sun is shin- 

 ing, as to make it impracticable longer to attempt the jarring of them do^nTi. From 



