The efficacies of biological and conventional chemical insecticides against two major insect pests of alfalfa (aphids and thrips) were compared in three sites across China’s alfalfa belt.  In addition, the persistence of the residues of chemical insecticides in alfalfa and their influence on the quality of alfalfa hay were examined.  Efficacy varied among the different biological and chemical insecticides.  The chemical insecticides were significantly more effective than biopesticides in a short time-frame.  The efficacy period of biopesticides was significantly longer than that of chemical insecticides, and the corrected mortality rate of aphids in all regions was above 50% at 14 days after application.  The analysis of pesticide residues showed that the residual doses of all the pesticides were within the allowed ranges after the safe period.  The acid detergent fiber and neutral detergent fiber contents in alfalfa hay were higher and the protein content was lower in chemical insecticide treatments than in biopesticide treatments in Hebei.  The relative feeding value of alfalfa hay treated with Metarhizium anisopliae IPP330189 was the highest among the treatments.  Compared with chemical insecticides, the yield of alfalfa hay was higher in the biopesticides treatments.  Biopesticides show a stronger control effect on insect populations and also a better improvement in the quality of alfalfa hay than chemical insecticides.  This study provides a basis for exploring and developing a comprehensive control regime for alfalfa insect pests in the different alfalfa-growing regions in China, and for reducing chemical insecticide usage and improving forage quality.

Having an estimated production of 388 million tons in 2017 (FAO 2019), potato is one of the world’s most important food crops, along with rice, wheat, and maize.  Potato plants can adapt to different agricultural environments and are widely grown over many latitudes and elevations (Douches et al. 2004).  In addition to its consumption in Europe, North America and countries of the former Soviet Union, potato is now also popularized in Africa and Asia, especially in the developing countries including China and India.  Since 2015, China has been boosting potato production to become the fourth major crop produced in the country following rice, wheat and maize (Zhang et al. 2017; Xu et al. 2019).  And developing potato as the staple food was also included by Ministry of Agriculture and Rural Affairs of China in its important agenda.  Further improvement of potato production globally could promote the sustainable development of agriculture and safeguard world’s food security in the near future.
Insect pests are one of the major constraints to commercial production of potato in the world.  For over
8 000 years since its domestication in the central Andes, the potato has been plagued by a number of serious insect pests (Radcliffe 1982).  These include some of the most prolific and adaptable species known to human.  If left uncontrolled, the insect pests can completely destroy the affected crops.  With the rapid development of international trade, many insect herbivores of crops have spread across the continents along with agricultural products, and soon outbroke and became serious pests in their colonized areas (Carrillo et al. 2019).  To deal with the potato insect pest problems, currently several issues remain to be solved: (1) Know these insect pests.  A deep decoding of the biology and ecology of the potato insect pests is the basis for developing counter-measures to them.  (2) Know how the insects come and where they will go.  Figuring out the spreading of the invasive insects of potato can help achieve a better prevention and slow down their damage risks.  (3) Know their helpers during the harm to crops.  The co-occurrence of insects and plant pathogens in potato fields requires the raveling of how they interacts.  (4) Know the integrative management strategies.  Insect management in commercial potato production is heavily reliant on synthetic backlash and causing environmental pollution, and thus new strategies are needed to achieve a more ecological control of these pests. 
As guest editors, we are pleased to present 12 papers about the biology, ecology and management of major insect pests damaging on the potato crop in this special focus of the Journal of Integrative Agriculture.  We hope to improve our understanding of insect pests of potato and provide guidance for countries facing the IPM of those pests worldwide.  The 12 papers are organized into the following four sections.
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The potato tuberworm Phthorimaea operculella Zeller, is one of the most important potato pests worldwide including China.  Several reports indicate that P. operculella could be controlled biologically by the use of beneficial fungus such as Beauveria bassiana (Bals.-Criv) Vuill.  However, limited information is available under growing conditions in China.  Thus, this study evaluated the sub-lethal effects of B. bassiana on the offspring of P. operculella by the age-stage, two-sex life table.  First instar larva of P. operculella were treated with 1×10⁷ conidia mL–1 of the fungus, and several biological parameters were evaluated.  The fecundity, duration of the egg stage, all larval stages, pre-adult stage, and total pre-oviposition period, were significantly shorter than the control treatment.  Offspring of treated parents, presented a net reproductive rate and mean generation time of 17.43 per day and 24.98 days, respectively, compared to 65.79 per day and 26.51 days for the untreated ones.  This study provides basic information to help understanding the potential long-term effects of entomopathogenic fungi on P. operculella.

    The western flower thrips, Frankliniella occidentalis, is one of the most destructive sucking pests of vegetables, fruits and ornamental crops in China. Spinosad is one of the most commonly used insecticides to manage thrips. To assess the incidence of spinosad resistance in F. occidentalis field populations in eastern China, survival rates for 24 different populations were compared with those of a susceptible laboratory strain. All populations showed significantly higher resistance to spinosad compared with the control as determined by comparing median lethal concentrations. Two populations from Shouguang and Liaocheng in Shandong Province were classified as having moderate and high levels of resistance to spinosad with a mean resistance ratio of 17.0 and 89.2, respectively. Our research indicates a widespread reduction in spinosad efficacy for controlling F. occidentalis field populations, and that resistance management strategies should be implemented as soon as practicable, to reduce the potential of progressive resistance development and loss of efficacy.

The entomopathogenic fungus Beauveria bassiana (Balsamo) Vuillemin and predatory mite Neoseiulus barkeri Hughes are effective biological control agents of Frankliniella occidentalis Pergande (Thysanoptera: Thripidae), one of the most important pests of ornamentals and vegetables world-wide. Combined application of both may enhance control efficiency. The functional response for N. barkeri on the first instar larvae of western flower thrips which were infected by B. bassiana for 12 and 24 h in the laboratory ((25±1)°C, (70±5)% RH, L:D=16 h:8 h) was determined. The virulence of B. bassiana against the second instar and pupae of the thrips attacked by N. barkeri were also tested. The results showed that N. barkeri exhibited a Holling type II functional response on treated thrips. After having been treated with the fungus for 12 h and then offered to the predator, thrips were more vulnerable to be killed by N. barkeri. The second instar larvae and pupae of the thrips which had been attacked by predatory mites were markedly more susceptible to B. bassiana infection than normal thrips; the cumulative corrected mortality of B. bassiana of the second instar and pupae which were attacked by N. barkeri were 57 and 94%, respectively, compared to 35 and 80% in controls on the day 8. These findings highlight the potential use of B. bassiana in combination with N. barkeri to control F. occidentalis.

Thrips are among the most important agricultural pests globally because of the damage inflicted by their oviposition,feeding, and ability to transmit plant viruses. Because of their invasiveness, a number of pest species are common to both China and the United States and present significant challenges to growers of a wide range of crops in both countries. Among the pest thrips common to both countries are four of the major global thrips pests, Frankliniella occidentalis (Pergande), Scirtothrips dorsalis Hood, Thrips palmi Karny, and Thrips tabaci Lindeman. This review addresses characteristics that enable thrips to be such damaging pests and how biological attributes of thrips create challenges for their management. Despite these challenges, a number of successful management tactics have been developed for various cropping systems. We discuss some of these tactics that have been developed,including the use of cultural controls, biological controls, and judicious use of insecticides that do not disrupt overall pest management programs. The exchange of this type of information will help to facilitate management of pest thrips, especially in regions where species have recently invaded. A prime example is F. occidentalis, the western flower thrips, which is native to the United States, but has recently invaded China. Therefore, management tactics developed in the United States can be adapted to China. Because further success in management of thrips requires a thorough understanding of thrips ecology, we discuss areas of future research and emphasize the importance of collaboration among different countries to enhance our overall understanding of the biology and ecology of thrips and to improve management programs for these widespread pests.