43 



advocated against it in an earlier paper [R.A.E., A, iv, 440] are quoted. 

 Experiments in a badly-infested turnip field showed that an orchard 

 sprayer used an excessive amount of spray material. An apparatus 

 was therefore devised which could be attached to a traction sprayer 

 for lifting the foliage in such a manner as to expose the underside of 

 the turnip leaves to the mist delivered by the nozzles of a potato 

 sprayer. Maintenance of high pressure is essential to success with 

 this apparatus. 



Many experiments have been concerned with the most injurious 

 orchard Aphids, the results of which have been discussed elsewhere 

 [R.A.E., A, viii, 30]. During 1918, no serious harm was done by any 

 of these species in orchards that were properly sprayed. 



The plum curculio [Conotrachelus nenuphar] was more seriously 

 injurious than at any time during the previous five years, the infestation 

 showing conclusively that the mere following out of a spraying schedule 

 is not sufficient protection against this pest. Clean cultivation early 

 in the season, followed by a cover crop not producing a dense sod, 

 the removal of stumps and the clearing of overgrown hedges will 

 destroy the hibernating quarters of this weevil and greatly reduce its 

 numbers. The potato flea-beetle [Epitrix cucumeris], cabbage cater- 

 pillars and June bugs were all more than usually abundant. The 

 rose-bug [MacrodactyUts subspinosus] appeared in such numbers 

 that the self-boiled lime-sulphur spray recently used against it in 

 apple orchards was in 1917 extended to grape, peach and cherry with 

 satisfactory results. The three tussock moths, Hemerocampa leucos- 

 tigrna, S. & A., Halisidota caryae, Harr., and H. tessellaris, S. & A., 

 attacked the foliage of elm, maple and other shade trees to an alarming 

 extent from August to October. 



In greenhouses Diarthronomyia hypogaea (chrysanthemum midge) 

 was found to have become estabhshed in many locaUties. The 

 small brown leaf-beetle, Typophorus canellus, F., var. quadrinotatus, 

 Say, was discovered riddling the foUage of roses under glass. Fumiga- 

 tion with hydrocyanic acid gas nearly exterminated it in August, 

 but it reappeared in October. 



One of the most important developments was the discovery of a 

 serious infestation of Popillia japonica, recently introduced from Japan. 

 It is expected that the State Department of Agriculture will undertake 

 a campaign for the eradication of this pest [R.A.E., A, vii, 511]. 

 Trioza alacris, a European PsylHd introduced into New Jersey, 

 apparently from Belgium, several years previously, attacks the foliage 

 of bay trees both under glass and in the open. There are two 

 generations in the field during the summer, the eggs being laid on the 

 underside of the leaves near the margins. Hibernation occurs on the 

 tree in the adult stage, the insects again becoming active when the 

 trees are removed from cold storage and placed outside. Fumigation 

 with hydrocyanic acid gas or tobacco during the winter destroys 

 the insects. " The infestation of Gryllotalpa gryllotalpa described in 

 the report for 1915 [R.A.E., A, v, 322] is still present, but does not 

 seem to have extended. The nests are searched for and destroyed 

 during June and July. The importance of scouting operations as 

 a means of preventing such infestations is emphasised. 



Experiments have been undertaken to determine the effect of 

 atmospheric humidity on the Angoumois grain moth.[S itotroga cerealella] 



(G4G) 



a2 



