lOfi INSECTICIDES, FUNGICIDES, AND AVEED KILLEKS. 



lime-arsenite bouillies in every case. Its greater adherence, increased 

 by the addition of ghicose, is such that it remains fixed on the organs 

 of the sprayed plants during the whole season. This adherence, 

 therefore, excludes it in all cases where the plants or the fruits treated 

 are intended for food. But, wherever that is not the case, lead 

 arsenite may replace copper arsenite. The bouillies are best made on 

 the spot ; 0'2 per cent suffices in most cases. But some parasites 

 require 0-7 per cent, and even 1 per cent. It is calculated that it 

 takes three to four times more of this bouillie to obtain the same result 

 as from that with an emerald-green basis. But the lead-arseniate 

 bouillie, consisting of a flaky precipitate, enables the poison to be more 

 uniformly distributed, and by its white colour shows the spots touched. 

 A preparation of arseniate of lead on the market called "Disparin," 

 contains lead oxide 49, arsenic acid 16. tar 4, water 31 = 100. Lead 

 arseniate is especially used against a butterfly whose caterpillar has 

 become quite a plague — 



Ocneria dispar, Sch., or Liparis dispar, L. {Bonihyx dispar, gypsy 

 moth). — 'Spraying with cupro-arsenical bouillies is without effect as 

 the caterpillars are capable of absorbing strong doses of copjoer arsenite 

 without dying. By the use of a 1 per cent lead-arseniate bouillie very 

 satisfactory results have been got in America. To destroy the cater- 

 pillars the spraying must be done at the time they are hatched, for the 

 young caterpillars are more sensitive than the adults. It is possible to 

 destroy 90 per cent of the young caterpillars and only 60-70 per cent 

 of the adults. This process, therefore, appears to give better results 

 than the gathering of the nests of eggs in winter. 



Leptinotarsa decemlineata (Colorado beetle). — Woods recommends 

 to destroy insects injurious to potatoes, such as the Colorado bettle, 

 altises, etc., a bouillie consisting of 0-24 per cent of lead arseniate. If 

 it be desired to combat cryptogamic parasites simultaneously there is 

 added to bouillie bordelaise 24 lb. of arseniate of lead per 1000 

 gallons. Lead-arseniate bouillie is in general use in America. The 

 following is, however, a list of the insects against which it has been 

 particularly recommended : (1) Galeruca luteola, Sch., on the elm ; 

 (2) Galeruca anthomelcena, Schr., on the elm ; (3) Crioceris asparagi, 

 L., asparagus beetle ; (4) Bkopobota Vacciniana, Pack., butterfly in- 

 jurious to the cowberry (whortleberry, Kii-kland) ; (5) Orthocraspeda 

 trima, Moore, butterfly injurious to the cacao tree (Zehntner) ; (6) 

 PliUella, Margantia, Mamest7'a, aphides, insects injurious to cabbages 

 (Garman) ; (7) Knnomos subsignaria, phalena of the apple (Garman) ; 

 (8) Carpocapsa Vomonella, codlin moth. Trials to destroy this codlin 

 moth were made with a bouillie l)Oi-delaise containing 6-12 lb. of lead 

 arseniate or of disparin per 1000 gallons. Gillete and Garman by its 

 use reduced the percentage of wormy apples from 50 per cent (on the 

 check trees) to 4 per cent. (9) EmpJiroctis chrysorrhea. — Weed ad- 

 vises to cut the nests in the spring and spray with lead arseniate on 

 the young caterpillars; (10) Grapholitha botrana (tinea of the vine). 

 — Slingerland recommends three sprayings with a 1 per cent bouillie 

 of lead arseniate, the first a little before flowering, the second after 

 flowering, and the third when the grapes are the size of a pea. 



