8-1: Short Sainmarij of onr KnowUfhje of the Frit-fiy 



Average yield in husheh per acre of Oats in England. 



1910 41-87 1913 38-50 



1911 39-03 1914 40-01 



1912 35-56 . 1915 40-52 

 Average yield in England for ten years 1901-1910 = 42-07. 

 Taking the ten year average to 1910 as a basis it will be seen that 



in 1912 when frit-fly attacks were very bad the yield was reduced by no 

 less than 6| bushels per acre and as the acreage under oats that year 

 was 1,865,569 this would represent a loss of 12,126,198 bushels. 



PLANTS ATTACKED. 

 Rye, oats, barley, wheat, maize, and various grasses {Bronnin sp., 

 Poa annua, Poa pralensis, Triticuni repens, Triticum cristatum, Phleum 

 'pratense, Alopecurus pratensis, Milium ejfusum, Lolium perenne, Festuca 

 pratensis, Avena flavescens, Arrhenalherunt avenaceum and its var. 

 hidhosum). In England spring oats are chiefly attacked, though attacks 

 have been recorded on winter oats, winter and spring wheat, barley, 

 rye and grasses. Attacks are most common (or most noticeable) on the 

 young plants, and these plants must not be far advanced in growth 

 (Ritzema Bos, 1891); but the larvae of the third brood will feed in the 

 panicles of oats still hidden in the sheath {Board of Agric. Rep. on Inj. 

 Ins. in 1892), or in the young corn in the panicle, more rarely so far as 

 the British Isles are concerned in the ears of barley {ride under " Imago" 

 and Theobald (1906), and Text Book Agric. Zool 1899), while the only 

 records traced of larvae living in the ears of wheat are the breeding of 

 0. granarius from a wheat kernel by Curtis {Farm Insects) and Carpenter'^ 

 record (1909) of O.frit received "early in October from Queen's County 

 where they had been found on newly threshed wheat.'" According to 

 Ritzema Bos (Zeitschr.f. Pflanzenkr. i, 1891, p. 347) the females of the 

 second brood will only lay their eggs on the blossoming oats, and 

 when oats have been attacked in the spring the flies produced from the 

 larvae making this attack are very rarely on the wing in time to find 

 the oats in blossom, and consequently have to oviposit on wild grasses ^ 

 It would appear that the flies when able to choose between oats and 

 barley prefer the oats, for Miss Ormerod in her Report for 1888 statetl 

 that where "dredge corn " (barley and oats mixed) is planted, the maggot 



' This was not the caso in exporiincnts ciirricd out l)y the Dopartiiiont in liHS. lato 

 sown oats growing in tho same field as those sown earlier hein;,' I>adly atla.ki'd l.dth in 

 the young plant and in the rijx'ning grain. 



