192 Darling's Address upon Injurious Insects. 



of aphis. Thus the cabbage-louse is wholly unlike that of the peach ; 

 which again is quite different from that of the plum. They exist of every 

 color, green, black, blue, brown, brick-red and crimson — of all sizes from 

 that of a pea-bug to that of a mite just visible — naked, or covered with meal 

 or wool. Trees are not often killed by it, but they are checked in their 

 growth, and made to become crooked and deformed. When the plant-lice 

 fasten themselves upon the roots of herbaceous plants, as some species do, 

 they prove fatal. The ladies may have observed their China Asters in par- 

 ticular, to turn yellow, stop growing and finally perish, without any visible 

 cause. The grower of watermelons, too, sees the leaves of his vines be- 

 come smooth and glassy, and after a few days die. This is caused by the 

 aphis on the roots of the Aster and Melon. The powers of increase, given 

 to this insect, cannot be contemplated without amazement. Reaumur, from 

 the most careful observation, estimated that a single aphis might be the 

 progenitor of near six thousand millions in one summer. Well might Dr. 

 Darwin fear that ' their countless numbers might, in process of time, 

 destroy the vegetable world.' And yet, perhaps, there is no insect so com- 

 pletely in our power as this. We have only to put in practice the great 

 rule of farmers, to do every thing at the proper time, and we protect our plants 

 wholly from this insect with little labor. You see, to-day, a plant-louse 

 upon the leaf of a cherry tree. You neglect to destroy it, and to-morrow 

 there are 25 — in 22 days more, there are 50,000, and in one day after that, 

 there are more than 100,000. A touch of your finger, on the first day of 

 the month, may save you, therefore, the labor of a week, with soap-suds 

 and syringes, at the end of the month. Destroy the first that come in spring, 

 and the business of killing plant-lice is finished for the season. We are in- 

 formed by Huber, that the ants of Switzerland take into their keeping sev- 

 eral species of plant-louse, which they tend with the utmost care for the 

 sake of their honey, as a dairyman tends his cows for their milk. We have 

 evidence that the small brown ants which you see coursing up and down the 

 stems of cherry and peach trees, with great animation, take charge of some 

 of our plant-lice, in a similar manner, particularly those of the cherry tree, 

 and those on roots — that the ants house them in winter, and place them on 

 leaves at the opening of spring. Accordingly, the aphis generally is first 

 to be found very near the ground. There search them out and destroy them. 

 If unfortunately they escape your attention till they have multiplied to a con- 

 siderable extent, you may still master them with proper applications. One of 

 the best of these applications for trees, is a strong solution of ivhale-oil soap. 

 The ends of the branches may be bent over, and held in the soap-icater about 

 a fourth of a minute. A small paint brush, dipped in the wash, may be used 

 in some cases, especially on cabbages, and on the branches of pear trees, 

 infested with that species, which collects about the buds, and produces a 

 black rust. Common soap-suds, warm and strong, will serve to kill the 

 aphis, but it is apt to kill leaves also. A decoction of tobacco is a sure 

 destroyer of the aphis. It cannot be used upon leaves ; but nothing, per- 

 haps, is better to pour around the roots of plants, when those parts are in- 

 fested by the insect. President Dwight preserved his watermelons 'by 



