Preliminary evaluation of the control effect of two predatory mite species on Eotetranychus sexmaculatus in rubber trees in Hainan Province, China

In this study, we aimed to clarify the effect of predatory mites on controlling the rubber tree pest mite Eotetranychus sexmaculatus (Riley) and explored basic application of the biocontrol technology “using predatory mites to control pest mites” to rubber trees. We selected two commercial species with high predation capacity from five species of predatory mites for further field-release tests. The results showed that among the five predatory mite species, Phytoseiulus persimilis (Athias‐Henriot) and Neoseiulus cucumeris (Oudemans) showed the highest and lowest daily average predation amounts on E. sexmaculatus, respectively, and that the commercial predatory mites Amblyseius swirskii (Athias‐Henriot) and Neoseiulus barkeri (Hughes) were demonstrated relatively high predation capacities on E. sexmaculatus and represent the ideal species for field release. Additionally, we found that field release by a hanging release sachet was suitable for a low field-population density of pest mites, and that predatory mites could be released at a dose of one sachet per tree and/or every other row or every other tree according to the actual situation of the pest mites. If the field population of E. sexmaculatus is at the peak egg-laying period, the release of A. swirskii should be top priority, which will lead to high control efficiency within 2 to 3 weeks. In case of low field-population density of E. sexmaculatus or a rainy season, top priority should be given to the release of N. barkeri, which might lead to high control efficiency within 3 to 4 weeks. The results showed that the release of A. swirskii had a more fast-acting effect with a higher control efficiency than N. barkeri at the early stage of release, whereas N. barkeri exhibited a better release effect with greater persistence than A. swirskii at the late stage of release.

Advances in Mass Rearing Pseudophilothrips ichini (Hood) (Thysanoptera: Phlaeothripidae), a Biological Control Agent for Brazilian Peppertree in Florida

Pseudophilothrips ichini is a recently approved biological control agent for the highly invasive Brazilian peppertree in Florida, USA. Prior to approval for field release in 2019, thrips colonies used for host specificity testing were produced and maintained in small cylinders to fit in restricted quarantine spaces. This next segment in the classical biological control pipeline is mass production and distribution of P. ichini. To accomplish this, we developed novel techniques to expand from small colony maintenance to large-scale production. We first quantified the productivity of the small cylinders, each containing a 3.8 L potted plant and producing an average of 368 thrips per generation. Given the amount of maintenance the cylinders required, we investigated larger cages to see if greater numbers of thrips could be produced with less effort. Acrylic boxes (81.5 × 39.5 × 39.5 cm) each contained two 3.8 L plants and produced an average of 679 thrips per generation. The final advancement was large, thrips-proof Lumite® screen cages (1.8 × 1.8 × 1.8 m) that each held six plants in 11.4 L pots and produced 13,864 thrips in as little as 5 wk. Screen cages and cylinders had the greatest thrips fold production, but screen cages required ten times less labor per thrips compared to either cylinders or boxes. The efficiency of these large screen cages ensured sustained mass production and field release capacity in Schinus-infested landscapes. The screen cage method is adapted and used by collaborators, and this will expand the literature on beneficial thrips mass rearing methods.

Hypoxia combined with chilling maintains the quality of irradiated Drosophila flies: a simulated shipment experiment

Drosophila suzukii is an invasive fruit pest in Europe and America. Females lay eggs into mature fruit that larvae consume causing important losses. Sterile insect technique (SIT) is under development to control this pest. The efficiency of this technique relies on insect quality. However, during the process from mass production to field release, several steps may compromise insect quality and therefore SIT success. Shipment of sterile insects after irradiation is a key step of SIT programmes. Generally, insects are shipped as pupae and conditions during transport need to be adapted to prevent emergence before field release, while guaranteeing insect quality. To do so, transport is usually performed under low temperature, hypoxia or a combination of both. However, the impact of multiple stressors such as irradiation followed by chilling combined with hypoxia is poorly described and has not been studied in D. suzukii. Therefore, the aim of this study was to simulate a shipment of D. suzukii pupae (irradiated or not) under different conditions (chilling combined or not with hypoxia) for various durations, and to assess consequences on emerged adults. Irradiation followed by hypoxia and/or chilling only weakly altered emergence. However, 48 h of hypoxia without chilling altered the flight ability of flies whether or not they were irradiated. Conversely, when hypoxia was combined with chilling, flight ability remained similar to that of untreated flies. The use of chilling in combination with hypoxia for 48 h could be implemented as a transportation method for SIT programme on D. suzukii.

Assessing the Potential of Inoculative Field Releases of Telenomus remus to Control Spodoptera frugiperda in Ghana

In response to the threat caused by the fall armyworm to African maize farmers, we conducted a series of field release studies with the egg parasitoid Telenomus remus in Ghana. Three releases of ≈15,000 individuals each were conducted in maize plots of 0.5 ha each in the major and minor rainy seasons of 2020, and compared to no-release control plots as well as to farmer-managed plots with chemical pest control. No egg mass parasitism was observed directly before the first field release. Egg mass parasitism reached 33% in the T. remus release plot in the major rainy season, while 72–100% of egg masses were parasitized in the minor rainy season, during which pest densities were much lower. However, no significant difference in egg mass parasitism was found among the T. remus release plots, the no-release control plots and the farmer-managed plots. Similarly, no significant decrease in larval numbers or plant damage was found in the T. remus release fields compared to the no-release plots, while lower leaf and tassel damage was observed in farmer-managed plots. Larval parasitism due to other parasitoids reached 18–42% in the major rainy season but was significantly lower in the minor rainy season, with no significant differences among treatments. We did not observe significant differences in cob damage or yield among the three treatments. However, the lack of any significant differences between the release and no-release plots, which may be attributed to parasitoid dispersal during the five weeks of observation, would require further studies to confirm. Interestingly, a single application of Emamectin benzoate did not significantly affect the parasitism rates of T. remus and, thus, merits further investigation in the context of developing IPM strategies against FAW.

Bioremediation

Environmental bioremediation is the use of biological activity to reduce the concentration or toxicity of a pollutant. A rapidly increasing population leads to a consequential increase in industrial waste and pollution, and innovators are researching numerous techniques to degrade these pollutants and prevent their spread into the environment. These techniques are expensive and often result in secondary pollutants, which limits their widespread application. Bioremediation, however, presents a cost-friendly and more efficient way to degrade pollutants with little or no secondary pollutants. This Article explores how scientists can use genetically modified microorganisms (“GMMs”) to target specific hazardous wastes that are otherwise not degradable. Current U.S. laws and regulations only regulate GMMs on a case-by-case basis. With the rapidly advancing biotechnology sector, GMMs can provide cleaner, safer, and faster methods for cleaning up pollutants. However, as with all new sciences, GMMs pose unique risks when released directly into the environment. Regulations on the field release of GMMs are highly restrictive and hinder scientific research. This Article describes bioremediation and its potential risks; sets forth the current legal framework; and analyzes how policymakers can ensure the safe experimentation and eventual widespread use of GMMs in the environment.

Introducing iFluid: a numerical framework for solving hydrodynamical equations in integrable models

We present an open-source Matlab framework, titled iFluid, for simulating the dynamics of integrable models using the theory of generalized hydrodynamics (GHD). The framework provides an intuitive interface, enabling users to define and solve problems in a few lines of code. Moreover, iFluid can be extended to encompass any integrable model, and the algorithms for solving the GHD equations can be fully customized. We demonstrate how to use iFluid by solving the dynamics of three distinct systems: (i) The quantum Newton's cradle of the Lieb-Liniger model, (ii) a gradual field release in the XXZ-chain, and (iii) a partitioning protocol in the relativistic sinh-Gordon model.