DIAMOND-BACK MOTH. 
75 
you can help us to some knowledge of the life-history of this new 
enemy, which promises to be as destructive as the fly which attacks 
the leaves of Beet.” 
With regard to remedies, the treatment for Turnip Sawfly attack 
(see previous Reports) appears best, that is, all measures to secure good 
growth ; likewise brushing of the caterpillars with boughs in whatever 
way may be most convenient; and also not hoeing or singling when 
bad attack is present. Probably diminishing the wild plants which 
attract the Moth would also make a difference. 
I am favoured by a note from Lord Walsingliam of Plutella 
cruciferarum having been remarkably abundant this year, and of his 
having found the caterpillars feeding in great numbers on Sisymbrium 
Sophia (the fine-leaved Hedge Mustard or Flixweed). 
This caterpillar also feeds on other plants of the Cabbage tribe, as 
“ Jack-by-tlie-Hedge,” which grows on hedge-banks, “ Wall Mustard,” 
and others. It also frequents the Salsola Kali, or Saltwort, a plant 
very nearly allied to the very common Goosefoot and Oraclie of the 
fields, but which grows by the sea-sliore, and may have to do with the 
attack of the Diamond-back being often noticed near the coast. 
Note .—The following very good observation of attack in Caithness, 
which I consider very likely to have been caused by the Diamond- 
backs, was sent me by Mr. George Brown, of Watten Mains, Caithness, 
but to my regret I was unable, at the time of receipt, to identify the 
caterpillars with certainty; therefore, as the account of such wide¬ 
spread damage is of considerable value, both in itself and for future 
reference, I give the report as a note :— 
“ But the most persistent pest of the season on our Turnip crop is 
that of the insect of which a specimen caterpillar was sent you some 
time ago. Its ravages on the leafage have been very great, so much 
so that on many fields, especially along the sea-board, fears are enter¬ 
tained that the plant cannot bulb. Driving round the coast the other 
day [date of letter, Oct. 3rd. —Ed.] we were much struck by the 
appearance of the leaves ; they looked as if the crop had been thickly 
powdered with quick-lime. On close inspection the green parts of 
the leaves were found to have been completely eaten away, and the 
remaining membrane was so punctured in every part that it forcibly 
reminded one of white net, or still thinner web. Their manner of 
feeding is somewhat different from Sawfly caterpillars ; they descend 
the leaf-stalk and conceal themselves during the day in the heart of 
the top where it joins the bulb, and come out at night to feed all over 
the leaves.” 
