Control of cotton pests and diseases by intercropping:A review

Cotton(Gossypium hirsutum L.)is a globally important crop that is often damaged by pests and diseases.Current cotton pests and diseases management is dependent on chemical pesticides.Although chemical pesticides are usually effective,long-term application of these pesticides often leads to increased insecticide resistance in the pests,fewer natural enemies,reduced natural control,and a degraded environment.Because of increased environmental awareness and the need for sustainable cotton production,the control of cotton pests and diseases using biological means like intercropping is increasingly receiving attention.Intercropping of cotton with other crops can often boost the total yield and output of the intercropping system and provide significant economic benefits without sacrificing cotton quality.Intercropping also increases the number of natural enemies,and reduces the occurrence of cotton pests and diseases by altering the ecological structure and environmental conditions in the fields.Cotton-based intercropping is an effective strategy to reduce the competition between cotton and grain or other economic crops for arable land.It is also an important way to increase the populations of natural enemies in cotton fields for the management of pests and diseases.However,inappropriate intercropping can also increase labor requirements and even result in inadequate control of pests and diseases.This review focuses on the performance and the mechanisms of intercropping for reducing cotton pests and disease as well as on the effective management of intercropping systems.The risks and limitations,as well as the study approaches needed and the prospects of intercropping for the control of cotton pests and diseases,are also discussed.This information is intended to aid researchers and growers in designing economically viable and ecologically friendly pest and disease management strategies that will reduce the use of chemicals and the cost of cotton production.

Safety Analysis of Flow Parameters in a Rotor-stator Cavity

In order to ensure the safety of engine life limited parts （ELLP） according to airworthiness regulations, a numerical approach integrating one-way fluid structure interaction （FSI） and probabilistic risk assessment （PRA） is developed, by which the variation of flow parameters in a rotor-stator cavity on the safety of gas turbine disks is investigated. The results indicate that the flow parameters affect the probability of fracture of a gas turbine disk since they can change the distribution of stress and temperature of the disk. The failure probability of the disk rises with increasing rotation Reynolds number and Chebyshev number, but descends with increasing inlet Reynolds number. In addition, a sampling based sensitivity analysis with finite difference method is conducted to determine the sensitivities of the safety with respect to the flow parameters. The sensitivity estimates show that the rotation Reynolds number is the dominant variable in safety analysis of a rotor-stator cavity among the flow parameters.