116 



SCIENTIFIC AGRICULTURE 



March, 1921. 



Some Notes on the Fruit Worms of British Columbia 



By R. C. Treherne, Entomologist in charge for British 

 Columbia. Dominion Department of Agriculture. 



Owing to the similarities that exist between the var- 

 ious fruit-infesting larvae attacking orchard trees in 

 Canada, tlie following notes are given to assist field in- 

 sjiei'tors, horticulturists and entomologists in tiie ready 

 determination of species. Tlie importance of this study 

 is particularly essential so far as British Columbia is 

 concerned, owing to the absence, at the present time, 

 of the Oriental Peacli Moth and the comparative scarcity 

 of the Codling Moth within the province, and in as 

 much as it may assist in the rapid determination of 

 larval identity. 



The following fruit-infesting insects, liable of con- 

 fusion with the Codling Moth, have been taken in 

 British Columliia. and they fall according to Fracker 

 (Illinois Biological Monograph, 2, No. 1, 1915) whose 

 method of larval determination has been followed in 

 the main, into the following groups: — 



Tortrieinae — Tmetocera oceUutm. TIhe Apple Bud ]\Ioth. 

 Cydia pomondhi, The Codling Moth. 

 Peronea {Acleris) majrimana. 

 Archips (Cacoecia) rosaceana. 

 Archips {Cucoecia) argyrospila. 

 Enarmoma prunivoia, The Lesser Apple 

 Worm. 

 Cracilai'iidae — Marmara pomoneUa. The Apple Fruit 



Miner. 

 (Jclccliiidac— .-Idar.s-w liiiratcUa. The Peach Twig Borer. 

 Aristotelia frarjariae. The Strawberry 

 Crown Borer. 

 GScoplioridae — EpicalUma dimidiella. 

 Pvralidae — Plodia iiiterpuiictella. The Indian Meal 

 Moth. 

 Mineola tricolorella. 

 Geometridae— i?rtr/!f7(/ bruceata. Brace's Mcasurinir 

 Worm. 



Key to Certain Families (adapted from Fracker). 



A. Tlioracic legs wanting or mere fleshy swellings; body 



never fusiform: ocelli six or one on each side; body 



often depressed Gracilariidae. 



AA. Thoracic legs pi-esent. Prolegs always present but 

 when reduced represented by at least rudimentary 

 crochets; body having no tufted or secondary 

 setae; prolegs not bearing more than four or five 

 setae; crochets usually arranged in a circle or in 

 transverse bands; epsilon on prothorax always be- 

 low alpha and gamma. 



B. Kappa group on prothorax bisetose. theta absent : 



crochets usually biordiual Pyralidae. 



BB. Kappa group on prothorax trisetose. theta present. 

 V. Crochets arranged in two uniserial transverse bands 



on each proleg. those of anal pi-olegs in two groups. 



Gelechiidae. 



CC. Crochets arranged in a uniserial circle; pi grouji 



on mesothorax uniseto.se. 

 D. The setae beta closei- together on segment 9 than on 



any other abdominal segment, usually on the same 



or adjacent pinacula Tortrieinae. 



DD. The setae beta at least as far apart on segment 9 



as on any other abdominal segment, never borne on 



the same or adjacent pinacula. 



E. Crochets biordinal; fourth ocellus much closer to 

 third than to the sixth, second closer to third than 



to fourth QCcophoridae. 



EE. Third ocellus not .so closely associated with second 



and fourth Gelechiidae. 



The Apple Fruit Miner, Marmara pomoneUa, may be 

 readily distinguished from all other fruit-infesting in- 

 sects by its fruit mining habits, galleries being formed 

 between tlie flesh of the fruit and the skin. This insect 

 has been recorded from the Lower Kootenays and from 

 Sorento, both localities being in the humid transitional 

 areas of British Columbia. 



The Pyralidae, as pointed (uit in the foregoing key, 

 may readily be distinguished by the bisetose kappa group 

 on the prothorax. Fui-thermore the |)i group on the 

 mesothorax agrees with Fracker in being unisetose, and 

 kappa and niu on abdominal segment 9 while as.sociated 

 with eta in the specimens here examined is not ne- 

 cessarily on the same pinaculum. The two species men- 

 tioned in this group have both been received at the 

 labcn-atory, from field collections, in mistake for Codling 

 Moth larvae, in that both species have been taken in 

 fruit on the trees and under bands of burlap in the 

 quarantined Codling Moth areas. Mineola tricolorella 



x 



V 



Work of the Apple Fruit Miner (Marmora pomoneUa) on 

 apple. (Original.) 



was found to cause a feeding area on the surface of the 

 fruit very similar in appearance to the work of the 

 Lesser Apple AVorm or even 'side-worm' Codling Moth, 

 in that a small hollo wed-out area was produced just 

 beneath the skin. Full-grown larvae 12 mm. in length, 

 have been taken in the field within ai)|)le fruit, feeding 

 at the core and destroying the seeds, and the channel 

 from the surface feeding-area to the core while some- 

 what winding in nature was definite in outline. Fif- 

 teen larvae of this species have been taken in two yeai-s 

 in the vicinity of Vernon, B.C. on the habits of winch 

 tlie above notes have been taken. 



Lai'val characters. Mineola 1i iculorella. 



Mature larva 12 mm. in length, of even breadth, cylin- 

 drical, reddish-brown in colour, darker on the thor- 

 acic segments. In lateral aspect the ventral surface 

 is distinctly lighter than the dorsum. Head reddisli- 



