Production and field evaluation of codling moth granulosis virus for control of Cydia pomonella in the United Kingdom

Codling moth granulosis virus (Cp GV) was produced in larvae of Cydia pomonella reared on artificial diet. The average yield of virus (9 × 10⁹capsules/larva) was increased by raising the larvae on diet containing methoprene, a juvenile hormone analogue. In field trials in 1978 and 1979, one or two high-volume applications of Cp GV at 7 × 10¹⁰ capsules/litre achieved reductions in numbers of mature larvae and damaged fruit that were little different from those obtained by two applications of azinphos-methyl. A field trial in 1980 showed that at concentrations of Cp GV ≥ 6 × 10⁸ capsules/litre, damaged diminished slowly with increasing virus concentration. Following virus application in 1980, Cp GV infectivity was reduced by half in 3 days, but some activity persisted at least 4–8 wk after spraying. The results indicate that codling moth GV is an effective control agent particularly in reducing numbers of larvae and the more severe forms of fruit damage.     

The reproductive cycle, condition and feeding in Barbus liberiensis, a tropical stream-dwelling cyprinid

This investigation examines the biology of Barbus liberiensis , a small cyprinid living in the forest streams of Sierra Leone and Liberia, in relation to seasonal changes in the environment. The population studied showed a single discrete breeding season coinciding with the early part of the rains. Maturing fish previously marked moved upstream at this time. The pattern of gonad development is analysed and the relationship of fecundity to body size is defined numerically. The total and somatic (i.e. excluding gonad weights) condition of the fishes, relative to the length/weight data in September-November when the gonads are resting, reach a peak at spawning time for both mature males and females and for immature fish. The pattern of condition during a year differs in the two sexes.
B. liberiensis consumes a wide variety of foods but relies largely on insects and higher plant fragments. Debris from the forest canopy is an important source of nutriment. The fish feed, during the daytime and possibly at night, throughout the year. Experiments to determine the rate at which food passes through the gut are described and show that food passage is rapid.
The seasonal cycles in condition and reproduction are discussed in relation to cycles in some other tropical and temperate riverine fishes.     

Cellulose digestion in the locust,Schistocerra gregaria

An account is given of the bacterial flora of the alimentary tract of Schistocerca gregaria and the presence of cellulose digesting species is investigated.     

Evaluation of fungicides applied to soil to control naturally-occurring take-all using a balanced-incomplete-block design and very small plots

Six sterol biosynthesis-inhibiting fungicides representing several combinations of properties were applied to soil to control naturally-occurring take-all (caused by Gaeumannomyces graminis var. tritici) in winter wheat in field experiments in two successive years. The average take-all severity category was never more than moderate in the different clay-loam and sandy loam sites used in each year. At each site in each year there were six treatments and an untreated control in an arrangement based on a balanced-incomplete-block design for six treatments in 10 blocks each with three treatments. Each block had three treated plots and a control plot and was paired with the complementary block of three treatments (plus control) to form a complete replicate, of which there were 30 per site. Take-all assessments in June or July showed that after incorporation into the seed bed (at 2 kg ha“¹and sometimes at 1 kg ha”¹) in autumn, two non-volatile, strongly lipophilic compounds, nuarimol and triadimenol, with good intrinsic toxicity to the take-all fungus and slow rates of degradation, partially controlled take-all. However, another compound, flutriafol, with similar properties to nuarimol and triadimenol, controlled take-all less. Two slightly volatile, strongly lipophilic compounds, flusilazole and penconazole, with good intrinsic activity, were less effective (at 2 kg ha^-1). A volatile, less lipophilic compound, PP 969, with less intrinsic activity, also partially controlled take-all, but only after application as a drench in the spring (2 kg ha^-1). The most effective treatments were generally more effective the greater the level of disease (as indicated by assessments of disease in control plots), especially in spring assessments of disease. Although flutriafol did not perform as expected, it still seems reasonable to conclude that the requirements for a soil-applied fungicide to control take-all are likely to be: (i) good intrinsic fungitoxicity, (ii) some mobility in soil water (i.e. not strongly lipophilic), and (iii) season-long persistence.