Search

The orientation response after selective bilateral amputation of the antennae, maxillary palps and labial palps was used to determine the location of the CO2-receptive sensilla of larval Agriotes lineatus-obscurus (L.) and Limonius californicus (Mannerheim). The maxillary palps appear to be the most important for CO2 perception followed by the labial palps. The antennae did not appear to be involved in the orientation response. The CO2-receptive sensilla are likely among the cluster of sensilla at the tip of each palp. Scanning electron microscopy showed that there are more than twice the number of sensilla on the tip of the maxillary palp than on the tip of the labial palp of L. californicus larvae. The possible involvement of some of these sensilla in CO2 perception is discussed.

Granular fonofos, and granular AC 92100 [ O, O -diethyl S-( t -butylthio) methyl phosphorodithioate], each at 2 lb AI acre in-furrow, gave excellent protection of potatoes against wireworms in irrigated soils of southern Alberta. Fonofos was particularly effective over 2 consecutive years and provided better control than registered chlordane or carbofuran in-furrow broadcast. Chlordane and carbofuran were not significantly better than the checks in several tests, and HCS-3260 (alpha gamma chlordane) was no more consistent in its protection of potatoes than was chlordane. Fensulfothion, ( O, O -diethyl O-p -[(methylsulfinyl)phenyl] phosphorothioate), applied in-furrow or broadcast, gave variable tuber protection but appeared to be slightly better than chlordane or carbofuran. Fonofos, AC 92100, fensulfothion, and PP211 [ O, O -diethyl O -(2-diethyl-amino-4-methyl-6-pyrimidinyl) phosphorothioate] were as effective against the sugarbeet wireworm, Limonius californicus (Mannerheim), as against the prairie grain wireworm, Ctenicera aeripennis destructor (Brown).

Investigations on effect of method of application and placement of fonofos on its efficacy as a chemical control for wireworms, mainly Limonius californicus (Manner-heim), in Irish potatoes in Idaho were conducted at the Research & Extension Center, Aberdeen, for 3 years. Application methods used were broadcast, band-over, in furrow, and sidedress. Two areas of placement of sidedress treatments also were used: 50 mm to each side of the seed piece and at the same level; and 50 mm to each side and 50 mm above the seed piece. Significant differences in wireworm damage to potatoes due to different methods of application were noted in 2 of the 3 years. Furrow treatments resulted in less wireworm damage to tubers than any other method, with sidedress treatment giving control equal to or better than broadcast. Sidedress level with the seed piece resulted in significantly better results than sidedress 50 mm above in one of the years.