Compatibility and Efficacy of the Parasitoid Eretmocerus hayati and the Entomopathogenic Fungus Cordyceps javanica for Biological Control of Whitefly Bemisia tabaci.

Biological control is an effective method for whitefly management compared to the potential problems caused by chemical control, including environmental pollution and the development of resistance. Combined use of insect parasitoids and entomopathogenic fungi has shown high efficiency in Bemisia tabaci control. Here, we assessed the impacts of an entomopathogenic fungus, Cordyceps javanica, on the parasitism rate of a dominant whitefly parasitoid, Eretmocerus hayati, and for the first time also compared their separate and combined potential in the suppression of B. tabaci under semi-field conditions. Six conidial concentrations of C. javanica (1 × 103, 1 × 104, 1 × 105, 1 × 106, 1 × 107 and 1 × 108 conidia/mL) were used to assess its pathogenicity to the pupae and adults of E. hayati. Results showed that the mortality of E. hayati increased with higher concentrations of C. javanica, but these higher concentrations of fungus had low pathogenicity to both the E. hayati pupae (2.00-28.00% mortality) and adults (2.67-34.00% mortality) relative to their pathogenicity to B. tabaci nymphs (33.33-92.68%). Bioassay results indicated that C. javanica was harmless (LC50 = 3.91 × 1010) and slightly harmful (LC50 = 5.56 × 109) to the pupae and adults of E. hayati respectively on the basis of IOBC criteria, and that E. hayati could parasitize all nymphal instars of B. tabaci that were pretreated with C. javanica, with its rate of parasitism being highest on second-instar nymphs (62.03%). Interestingly, the parasitoids from second and third-instar B. tabaci nymphs infected with C. javanica had progeny with increased longevity and developmental periods. Moreover, experimental data from 15 day semi-field studies indicate that combined application of C. javanica and E. hayati suppresses B. tabaci with higher efficiency than individual applications of both agents. Therefore, combined applications of C. javanica (1 × 108 conidia/mL) and E. hayati is a more effective and compatible biological control strategy for management of B. tabaci than using either of them individually.

Biomechanical evaluation of porous bioactive ceramics after implantation: micro CT-based three-dimensional finite element analysis.

Hydroxyapatite ceramics have been widely investigated for bone regeneration due to their high biocompatibility. However, few studies focus on their mechanical characteristics after implantation. In this study, the finite element (FE) method was used to evaluate the mechanical properties of a fully interconnected porous hydroxyapatite (IPHA) over time of implantation. Based on the micro-CT images obtained from the experiments dealing with IPHA implanted into rabbit femoral condyles, three-dimensional FE models of IPHA (1, 5, 12, 24, and 48 weeks after implantation) were developed. FE analysis indicated that the elastic modulus gradually increased from 1 week and reached the peak value at 24 weeks, and then it kept at high level until 48 weeks postoperatively. In addition, as a local biomechanical response, strain energy density became to distribute evenly over time after the implantation. Results confirmed that the mechanical properties of IPHA are strongly correlated to bone ingrowth. The efficiency of the proposed numerical approach was validated in combination with experimental studies, and the feasibility of applying this approach to study such implanted porous bioceramics was proved.

Chemical precipitation for controlling nitrogen loss during composting.

Aimed at controlling the nitrogen loss during composting, the mixture of magnesium hydroxide (Mg(OH)( 2)) and phosphoric acid (H(3)PO(4)) (molar ratio 1:2) were utilized as additives to avoid increasing total salinity. In trial TA, the additives were put into absorption bottles connecting with a gas outlet of fermentor (ex situ method); in trial TB, the additives were directly added to the composting materials (in situ method). During the 26 day composting period, the temperature, pH, total organic carbon (TOC), total nitrogen (TN), ammonium nitrogen (NH(4)(+)-N), total phosphorus (TP), available phosphorus (AP) and germination index (GI) were measured. The experimental results show that the additives reduced the pH, while NH( 4)(+)-N and TN were obviously improved. NH(4)( +)-N was 11.9 g kg(-1) and 3 g kg(- 1) in amended compost trial (TB) and unamended compost trial (TA), respectively; TN increased from 26.5 g kg(-1) to 40.3 g kg(-1) in TB and increased from 26.5 g kg( -1) to 26.8 g kg(-1) in TA. Analysis of the TOC and carbon mass revealed that absorbents accelerated the degradation of organic matter. The germination index test showed the maturity of TB (102%) was better than TA (82%) in final compost. Furthermore, TP and AP were also obviously improved. X-ray diffraction analysis of precipitation showed that the precipitation in absorption bottle of TA was newberyite (MgHPO( 4) 3H(2)O), however, the crystal in the TB compost was struvite (MgNH(4)PO(4) 6H(2)O: magnesium ammonium phosphate). These results indicated that Mg(OH)(2) and H(3)PO( 4) could reduce the ammonia emission by struvite crystallization reaction. Optimal conditions for struvite precipitation should be determined for different systems.

[Application of struvite crystallization on co-composting of swine manure and cornstalk].

Aimed at controlling the nitrogen loss caused by the ammonia gas emission during composting, the mixtures of magnesium hydroxide [Mg(OH)2] and phosphoric acid (H3PO4) were added into composting materials of swine manure and cornstalk. After 26 d composting, ammonical nitrogen and total nitrogen were improved obviously,which were 10.7 g x kg(-1) and 36.9 g x kg(-1) respectively in amended treatment (B), while they were 7.7 g x kg(-1) and 26.8 g x kg(-1) in un-amended trial. By analysis of the total organic carbon, t suggested that amendments accelerated the degradation of organic matter, germination index test showed the maturity of trial B(96%) was better than trial A(82%) in final compost. The scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) analysis confirmed the existence of struvite (MgNH4PO4 x 6H2O). These results indicated that Mg (OH)2 and H3PO4 could accelerate the degradation of organic matter, and reduce the ammonia emission by struvite crystallization reaction.