Lejeune, R. R.

English

Journal of the Entomological Society of British Columbia

I h l~t<TmlOLO(;lr· A 1. SOCI ET Y o f B I<lTl RII. COL I.i MBIA. PRoW. I U159). VOL. 5 6 . NOL 4, U15!1 SPRAYING OPERATION FOR CONTROL OF THE BLACK-HEADED BUDWORM', VANCOUVER ISLAND, BRITISH COLUMBIA, 1957 R. R . LEJEUNE Forest Biology Laboratory, Victoria, B.C. During June, 1957, 196,000 acres of western hemlock on northern Van-couver Island, British Columbia, were sprayed to protect stands severely de-foliated for two consecutive years by the black-headed budworm. These stands, out of a total outbreak area of about two million acres, were con-sidered to be in critical condition. Surveys indicated that they could ex-pect to receive damaging defoliation in 1957. Although it was dwarfed by the extensive control programs in the western United States and eastern Canada there are some special fea-tures about the project that are worth relating. Organization As this was the first large control operation attempted in British Col-umbia, an organization was needed to plan and direct the proj ect and to provide a legal body for entering into commitments with governmental and private agencies. As a result the Brit-'ish Columbia Loggers' Association formed a permanent Pest Control Committee for this purpose. Repre-sentatives from the British Columbia Forest Service and the Forest Biology Laboratory serve on the Committee in an advisory capacity, but since this Association is composed of most of the logging companies in British Col-umbia, it can be considered that the project was directed by industry. The Forest Biology Laboratory was re-sponsible for spray and biological as-sessment. The Committee drew heavily on the experience acquired by other agencies in large-scale operations in the west-ern United states and eastern Can-ada, but local conditions necessitated modification of some procedures fol-lowed elsewhere. We now have an 01'-I Contribution No. 528, Forest Biology Division, Science Service, Department of Agriculture, Ot· tawa, Canada . ganization and a soundly established pattern tailored to British Columbia conditions for handling future forest insect control problems. Spray Equipment and Chemicals The spraying was done by four con-verted TBM Gruman Avengers. This was the first time these aircraft have been used for spraying forests in Can-ada . They were selected because the rugged terrain, the radius of action, and the uncertain weather conditions likely to prevail indicated that a larg-er aircraft than the conventional Stearman was needed. In our opinion their performance with respect to pay load and spray pattern was impres-sive. As a result, several of these air-craft have been purchased by a Cana-dian firm and have been used against the spruce budworm in eastern Can-ada. Since it was possible that the infes-tation could collapse at any time from natural causes, resulting in the can-cellation of the operation, raw mate-rials were stored and mixed as need-ed. Mixing and loading were done at the air base, where a mixing plant was constructed. The plant had a daily manufacturing capacity of about 30,000 gallons of spray and a storage capaCity of about 35,000 gal-lons. Spray was loaded into the air-craft directly from the mixing plant. The spray consisted of DDT in Stan-dard base oil diluted with diesel oil to yield a solution containing 1 pound of DDT per U.S. gallon with an emulsifier content of 1.64 per cent. The emulsi-fier was Atlox 2082A. The use of an emulsifier in 1956 (Brown et al., 1958) gave such satisfactory results that it was incorporated into the operational formulation in 1957. Efforts were made to compare the effectiveness of the operational spray with three other formulations. How-ever, in a pres::;ing mixing and flyin g schedule it proved unpractical to ex-ercise the precise control essential for experimental tests. Results indicated that as low as one-half pound of DDT per gallon per acre was as effective as the operational solution. Results with diesel oil without emulsifier were in-conclusive and plans to experiment with water instead of an oil diluent were cancelled altogether. Timing Black-headed budworm larvae de-velop more slowly than spruce bud-worm larvae and therefore provide a longer period for effective spraying. In 1956 it was found that all the lar-val stages were susceptible to the spray. Spraying can be started when roughly 50 per cent of the larvae are in the second instar and , for maxi-mum effect , should be completed be-fore the appearance of fifth-instar larvae . In 1956 and 1957 this allowed a period of about one month for treat-ment. Spraying in 1957 commenced on June 10, and despite delays caused by poor weather, was completed on June 20. Control Achieved The operation achieved its principal objective (Lejeune et al. , 1957) . Bio-logical assessment plots showed that the budworm was completely control-led where the spray deposit was ade-quate (over 10 drops per cm. 2 or .20 gal. per acre). Data obtained indi-cated that the spray deposit in gen-eral ranged from light to medium (1 to 20 drops per cm. 2). Deposits were lighter in areas skip-sprayed to avoid lakes, streams, cut-over areas and cedar swamps, and heavier where avoidance of specific landmarks was not required. The indicated average control of about 90 per cent, based on data from five sample plots, was suffi-cient to prevent serious defoliation in 1957. Fish Mortality When it was decid ed in the fall of 1956 to proceed with a spraying oper-ation in 1957, it was antiCipated that some commercial and game fish might be killed . Accordingly the decision was made known to the Federal and Provincial fisheries authorities, who were invited to have representatives at all subsequent meetings of the Committee. In co-operation with the Commit-tee, plans were drawn up by the fish-eries organizations to assess mortality of fish and fish food organisms. The main concern was for the fry of cohoe salmon and steelhead trout, which would be in the streams during the spray period. To minimize contamin-ation of waters, pilots were instructed to shut off the spray when flying over rivers and lakes, streams were not to be used as boundaries of spray blocks and, where feasible , pilots were to spray parallel to the course of major streams keeping one swath width away. Fisheries representatives, who were present on a ll flights made by the observation aircraft, were satis-fied that a sincere effort was made to implement these measures, but spray drift hit some lakes and streams and fish were killed. The effects of spraying were meas-ured in nine of the ten maj or salmon streams in the area (Crouter and Ver-non, 1959) . Results obtained indicated a large variation in the mortality of cohoe fry , ranging from zero to al-most complete annihilation. Losses were severe in four of the major streams, not only to cohoe but also to trout, steelhead yearlings, and pos-sibly alevins of trout and steelhead. The reduction of aquatic insects paralleled the loss of cohoe fry and the productivity of several streams may not return to adequate propor-tions for several years. The effects of spraying varied with each stream but some trends were noted. Fish mortality was high in large streams in flat terrain with dense forest cover, which made the streams difficult to see from low flying aircraft, and in large streams flowing through steep-walled valleys. Mortal-ity was low in streams in well-defined but not particularly steep-walled val-leys and in small streams with a dense overhanging canopy. 18 8JsTO~I O I.OUlC\ L SOCrF;TY OF' B HITl "Il CO LI' ~\fIH . \ . 1'1<0(,. (1 ~j 5 ~). VOl. . 56. Nov. 4, 195!J In June, 1957, 156,000 acres of west-ern hemlock were sprayed to control the black-headed budworm. The op-erational spray consisted of DDT in Standard base oil diluted with diese l oil to yield a solution containing 1 pound of DDT per gallon with an emulsifier of 1.64 per cent. Spray was applied at the rate of 1 gallon p er acre. The indicated average control of about 90 per cent was sufficient to prevent serious defoliation in 1957. Fish populations, particularly cohoe fry, and fish food organisms in some stream s were severely depleted . Summary Although there were a number of puzzling inconsistencies in results ob-tained from the assessment of fish mort a lity, it is clear tha t under the conditions of the operation, fish and fIsh food populations in some str eams were severely depleted . References Cited Brown, G. S., A. P. Randall, R. R. Lejeune and G. T. Silver. 1958. Black-headed bud-worm spraying experiments on Vancouver Island , British Columbia. For. Chron. 34: 299-306. Crouter, R. A. and E. H. Vernon. 1959. The effects of black-headed budworm control on salmon and trout in British Columbia. Canadian Fish Culturist 24 : 23-40. Lejeune, R. R., A. P. Randall and K. R. Elliott. 1957. Aer ial spraying operations for control of the black-headed bud worm, Vancouver Island , British Columbia, 1957. Interim Report 195'7-1. Forest Biology Laboratory, Victoria, B.C. (Multigraphed). THE DISTRIBUITION OF THE WHEAT MIDGE, SITODIPLOSIS MOSEL,LANA (Gehin), IN BRITISH COLUMBIA J. C . ARRANfJ A/Provincial Entomologisl The wheat midge, Sitodiplosi s mos-ellana (Gehin), was first reported in the Pacific Northwest in 1904 at Chil-liwack, B.C. Since that time it ap-pears to have spread through the province. It was lis t ed as a n import-ant pest of grain in the lower Fraser Valley in 1905. In 1921 serious d a mage was reported in the Salmon Arm dis-trict. A wheat field was damaged by this pest near Lumby in 1936 when there was also serious damage on Vancouver Island and in coastal dis-tricts. Light damage was recorded at Merritt in 1951 and at Nelson in 1953. In 1954 infestations were reported from Larkin, Armstrong and Enderby. Damage occurred on spring wheat at Revelstoke, Grindrod , Enderby and Salmon Arm in 1955 . In 1957 a h eavy infestation was examin ed in a fIeld of Garnet wheat at K ersely, south of Quesnel. Accord-ing to the farmer this field h a d been similarly infested in 1956 . In 1958 severa l fie lds were infested in the K er sely a r ea and serious d a mage oc-curred. This infestation appears to be so severe that unless it subsides it is questionable whether the farmers in the a rea can continue profitably to grow gr a in . The farmers report that fall whea t and ba rley as well as spring wheat have been attacked. In the literat ure , these grains as well as oats are list ed as hosts of the pest. Since the wheat midge h as become so well established at Kersely, it seems reasonable to assume that it may eventua lly move into the Peace River a r ea. References Reeher M. M. 1945. The Wheat Midge in the Pacific Northwest. U.S.D.A. Circ . 732. B.C. Dep't. of Agriculture Annual Report-1921, 1936, 1951, 1953, 1954, 1955, 1957, 1958. 

Spraying operation for control of the black-headed budworm, Vancouver Island, British Columbia, 1957

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Spraying operation for control of the black-headed budworm, Vancouver Island, British Columbia, 1957

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Journal of the Entomological Society of British Columbia