No. XV.B.] APPENDIX. 243 



Report on Aphides foe Maech 1847. 



During the past month I have been unable to add materially to our 

 knowledge of the ravages committed by these pests to the vegetable 

 kingdom. My f oi-mer obsei-vations have caused gai-deners to attend more 

 attentively to their existence, and I find that, in greenhouses and hot- 

 houses, so much more caa-e is taken of their annihilation than formerly, 

 that scarce any exist. 



I have found no vastator living out of doors, though other aphides 

 have, in some places, commenced their plant-killing labours. The peach 

 is, in some instances, affected, a fact to -which Mi-. Hurst (p. 196) has 

 called attention; but this aphis is not the vastator. The peach-trees 

 which I have examined have been perfectly free. My infected tulips and 

 crocuses are nearly all dead ; as they perish, it is curious to observe the 

 myriads of winged ones which leave : they collected the other day in such 

 swarms on my passage window that, in one comer of a pane of glass, 

 at least a piQ-box fuU were congregated together. On examining the 

 mangold-wuTzels, they are found in many places to rot; and, notwith- 

 standing that they have been packed in clamps throughout the winter, a 

 few vastators may be found on the young leaves, interspersed here and 

 there, showing that the cause of the rotting had been really present. I 

 have heard that the vastator is on the wheat in Ireland, but have been 

 unable to authenticate the fact. I beg that the com crops may be con- 

 tinually examined, and should feel greatly obliged for communications 

 upon this matter. The strawbeny plants which have the eggs of aphides 

 on their leaves have much suffered this winter. 



With regard to the potato plant, I have some Russian varieties 

 in perfect health in a greenhouse, showing that there is no atmospheric or 

 other cause but the vastator which is Kkely to produce the disease. 

 These Russian potatoes were a little damaged in their passage, neverthe- 

 less are healthy in structure. I have yet in my possession about one 

 hundred tubers, and it will afford me great pleasure to give one to any 

 applicant, that the seed may be extensively circulated. Those who 

 receive a tuber vnR perhaps do me the favour to furnish a short account 

 of the produce, and their power of resisting the disease, at the end of 

 the season. 



In my last report, I called attention to the probability of scarcity of 

 food, from the certainty of deficiency in the produce of potatoes next 

 season, and urged agriciilturists to plant, for it is impossible to foresee 

 whether the insect wUl recur this year. Experience shows that a certain 

 and large crop can only be obtained from whole tubers, or considerable 

 pieces of tubers ; therefore such sets are to be preferred. Nevertheless, 

 the produce from a single tuber may be increased by planting very wide 

 apart, and layering, or by taking shoots off, as they sprout from the 

 potato, and planting them. 



" I should be inclined to try the experiment of using but small por- 

 tions of the potatoes for sets — such as scooped eyes or potato-peelings — 

 although Marshall has ascertained that, under ordinary circumstances, the 

 crop is thereby materially lessened. These means would only be service- 

 able to restore the health of a diseased plant, not to arrest the malady at 

 its commencement. 



B 2 



