SYSTEMIC TREATMENTS FOR CONTROL OF CATTLE GRUBS HYPODERMA SPP. IN AN ISOLATED RANGE HERD

Abstract

The efiect on infestation by cattle gtubs Hypodenng spegiq of .six annual ."il"-i" i*".ticid"-ueatme-tits -m rridi"d in i-range he-ril isolated by at.least tb miles from locations where adiacent herds could have dro,ppe-d pupae. llrter t*o-tri.i-""tt tn" i"f".t"iion *li redrrced from 30.2 to-1.6 giubs per untreated calf. remaining at approximately this low level until after the fitth ffeeunent ;hilild;;r;rr"a i'.iO.i grubs'per untreated calf. After the sixth treatment ;i.;l"f;t.;;i"" p.ttitt"a;;i-z-!iout per untreated -c{f, arld', in the absence of insecticide .r""*"ni-ii trc iln-V"*, increased to 1O.2 grubs per untreated calf in-the sth v""t. S"-tn"i'fly'disiurbance-had -beeri-a long-standing herd manasement problem, but did not recur after the first systemrc lnsecncloe itJr,"i"'tii.-'uliJ-"tirg"tit"Jreiiiictea sampljng to-calves..Failure to eliminare Erubs *". "ttri6oftd to either high surviva-l of grubs in the unsampled maftr; animals, or to migration of female Hypoderm.a into the sp'ng rangei.These results piovide little basis for optimism concerning pJorects rn orgailze{ areas for control of grubs with single annual applicaflons ot cufrenuy availaDle systemic insecticides.

Efficacy of Crufomate on Cattle Grubs in Relation to Method, Rate, and Time of Application

“…Sept. 20, 1966 Oct. 28,1966 Nov. 22,1966 Nov. 4,1968 Dec. 3,1968 Nov. 4,1968 Dec. 3,1958 Nov. 4,1968 Dec. 3,1968 D.y (Breyev 196l Although the number of tests was small, the results were in agreement with those obtained elsewhere (Kinzer et al 1967 (Rich 1970), and for the final stages of eradication programs (Carpenter and Hewitt 1920;Rich 1965a). The relation of application rate of pour-on to grub reduction is particularly interesting (Fig.…”

Gonotrophic Development in Hypoderma lineatum and H. bovis (Diptera: Oestridae), with Notes on Reproductive Capacity

“…Even under intense control pressure, Hypoderma populations have an unexpected ability to rebound to precontrol levels (Rich 1965, Tarry 1984, Scholl et al 1986.…”

Failure of two consecutive annual treatments with ivermectin to eradicate the reindeer parasites (Hypoderma tarandi, Cephenemyia trompe and Linguatula arctica) from an island in northern Norway

“…Whatever the explanation for the failure to erad¬ icate the three parasite species, the experiment shows, as with similar experiments, that parasites are often difficult to eradicate under natural condi¬ tions. Several previous studies have shown that even under intense control pressure, oestrid popu¬ lations have an unexpected ability to rebound to pre-control levels (Rich, 1965;Breyev, 1973;Kummeneje, 1979;Scholl et al, 1986), most prob¬ ably because of their great dispersal potential, their high efficiency to transmit their progeny to the host, and, not the least, their high fecundity and the decreased immune response in hosts deprived of antigenic stimulation through contact with the parasite.…”