Predatory function of bifenazate- resistant strain of Blattisocius dentriticus Berlese

Abstract:【Objective】The objective of this research was to clarify the predatory functional response ofthe bifenazate-resistant strain of Blattisocius dentriticus to Panonychus citri and evaluate whether it waspossible to use the“alternative prey method”to raise B. dentriticus and whether it had the potential tobecome a natural enemy of citrus, which aimed to better coordinate the use of predatory mites and miticides,and to guide the effective combination of field chemical and biological control.【Methods】Resistancewas evaluated using biological assays conducted in a laboratory. The predatory effect of the equalclamp on the elliptic meal was determined by the method of Mcmurtry and Scriven. Round citrus leaveswith a diameter of 0.70 cm were placed in each groove of a six-concave slide with a diameter of 1.50cm and a depth of 0.22 cm, respectively. Aleuroglyphus ovatus at the density of 3, 6, 9, 12, 15, and 18heads was placed in each of the grooves, and the B. dentriticus was placed into a drop of sputum, eachof which was placed in a tongs (hungry after 24 h). It was covered with a cover slip to prevent cockroachesfrom escaping, and covered with a wet brush. A circle of water film was applied around the filmas isolation (4 h once), and the samples were put into the artificial climate chamber. Five temperaturetreatments was set separately and the predation effects were observed at 16, 20, 24, 28, 32 ℃ after 24hours. The relative humidity was (80 ± 5)%, the photoperiod was 14L: 10D, and each treatment was repeatedfor three times. The predatory functional response model of the B. dentriticus was fitted to theHolling disc equation,i.e., Na=αTN/(1+αThN). Where Na was the number of prey; α was the instantaneousattack rate; T was the total test time; N was the prey density, which was the initial access to the prey density; and Th was the time taken by the predator to process each prey. The test time was one day.The α/Th value was used to evaluate the predation ability of the equal clamp. 【Results】Holling Ⅱ functionalresponse equation could be obtained by linear regression. When the density of elliptic meal was3, 6, 9, 15, 18 per leaf at 16-28 ℃, the predation of elliptic meal increased with the increase of temperature.In the density, the predation reached a maximum at 28 ℃ and decreased slightly at 32 ℃. B. dentriticushad strong predation ability for elliptic meal in the range of 16-32 ℃. In the range of 16-28 ℃,the predation ability, attack coefficient and average predation increased with the increase of temperature,reached the highest at 28 ℃, and began to decrease at 32 ℃. The time to process the prey also decreasedwith increasing temperature, with the least at 28 ℃ and a slight increase at 32 ℃. The predationcapacity and daily average predation at 28 ℃ were the highest, 24.40 and 21.98 respectively, and thepredation ability and daily average predation at 16 ℃ were the smallest, being 5.49 and 8.41, respectively.Under different temperature conditions, the bifenazate-resistant strain and sensitive strain of B. dentriticuswere different in predation of eggs and female of P. citri. The overall trend was that the predationincreased with the increase of the number of prey, before the number of prey reached a certain level.The predation tended to be flat. In the range of 3, 6, 9, 12, 15, and 18 heads per leaf density, the predationreached a maximum at 28 ℃, and then decreased slightly with increasing temperature. The differencein predation at the same temperature was not significant. The B. dentriticus had strong predationability for P. citri. The changes in the average predation, predation ability and attack coefficient of B.dentriticus predation of eggs and female of P. citri were the same as those of the sensitive strains. Therewas no significant differences in the predation of female mites and eggs between resistant and sensitivestrains.【Conclusion】Resistance of bifenazate did not affect the predation function of the B. dentriticusto P. citri. Therefore, B. dentriticus had the potential to develop into a natural enemy. The results of thistest showed that B. dentriticus had good predation ability for elliptic meal, so it was recommended touse B. dentriticus to produce large-scale production and other clamps. The use of bifenazate for resistancescreening did not affect the predation function of the B. dentriticus on P. citri, and the resistanceof the scorpion bismuth phthalate was better applied to the B. dentriticus population.