Trapping effects of different color sticky cards and sex pheromone traps on Apolygus lucorum in jujube orchards

Abstract: 【Objective】Apolygus lucorum Meyer-Dür (Hemiptera: Miridae) is the main pest of cotton in the past, but it has gradually transferred to other crops in recent years.‘Lingwu Jujube'is an excellent fresh-eating jujube with local characteristics in Ningxia. With the annual increase of cultivation area and the change of modern management mode, the damage area caused by A. lucorum is gradually expanding, and the damage degree is increasing rapidly. At present, chemical control is the main measure to control A. lucorum in jujube orchards, but it is difficult to control its population by chemical control alone because of its strong diffusivity, serious overlap of generations and quick action. Therefore, it is particularly urgent to adopt other green prevention and control measures. As an effective physical means of pest control and population monitoring, sticky cards have the advantages of simplicity, friendly environment and high efficiency. At present, it has been widely used in greenhouses to control aphids, whiteflies, thrips and other pests. Insect sex pheromone trap is used based on the principle of synthetic sex pheromone to attract the opposite sex insect. It has the characteristics of high specificity, high sensitivity and no harm to natural enemies. Recently, most of the studies on the trapping of A. lucorum by sticky cards mainly focus on cotton, grape, corn, sunflower and other economic crops. And studies on jujube orchards have not been reported. Therefore, the objective of this study was to determine the temporal dynamics of the damage caused by A. lucorum in Ningxia, to evaluate the trapping effect of four-color sticky cards on orientation and field blocks of A. lucorum in jujube orchards, and to provide a scientific basis for comprehensive prevention of A. lucorum in the actual production.【Methods】Four types of sticky cards with different colors (green, yellow, blue, black) were compared in different direction (east, south, west, north and central) and different field (block A and B) of jujube orchards during late June to early October in 2017. There were three replications for each color treatment, and a total of 120 sticky cards were hung in two sample plots. The sticky cards were arranged randomly on the branches of jujube trees with sparse leaves. The sticky cards were hung 2-2.5 m above ground and the interval between the cards was 6 m apart, and the trapped insects were checked once in every 3 days and the sticky cards were replaced once in 10 days. The sex pheromone traps were used to investigate the temporal dynamics of the A. lucorum. Seventy-five sex pheromone traps were evenly suspended on a chessboard in 1 hm² jujube field. Sex traps were suspended on the branches of jujube trees with sparse leaves. The height of the traps was 2-2.5 m. The traps were investigated every 3 days and the collecting insect barrels were replaced every 10 days.【Results】The trapped insect numbers on green and yellow sticky cards in plot A (F=19.62, p = 0.0005) and plot B (F=19.62, p = 0.000 5) were higher than that on blue and black cards, and there was no significant difference between the green and yellow cards. The yellow (F=4.97, p = 0.018 2) and green (F=9.19, p = 0.002 2) cards attracted more insects than blue and black ones in any direction. The variation trend of the number of trapped insects by sticky cards and sex pheromone traps was basically the same. The most numbers of A. lucorum were trapped in the late June and early October, and only a few were trapped in late July and August. The number of insects trapped in the central area was more than that at the edge of the field.【Conclusion】Multi-way ANOVA analysis showed that trapped numbers of A. lucorum were significantly influenced by the different color (p<0.000 1) , direction (p < 0.000 1) and field (p = 0.004 3) , and there was a significant interaction between color and direction of sticky cards, but there was no significant interaction between field and color and direction. The sticky cards and sex pheromone traps were simple, environment-friendly and efficient tools for controlling A. lucorum, which were worthy to apply widely. Therefore, the following points should be paid attention to in the control of A. lucorum in jujube orchards. Early summer and early autumn in Ningxia region are the critical period for A. lucorum to damage jujube orchards. Green and yellow are the best color boards for controlling A. lucorum. When sticky cards are used, it is necessary to arrange the appropriate color, reasonable density, and suitable time according to the type of field vegetation, microclimate and surrounding non-crop habitat.