Tetranychus urticae Koch is a worldwide agricultural pest mite that feeds on more than 1100 kinds of crops. The mite has developed a high level of tolerance to high temperatures, but the physiological mechanism underlying the outstanding adaptability of this pest to high temperatures remains unclear. To clarify the physiological mechanisms of T. urticae in response to short-term heat stress, four temperatures (36, 39, 42, and 45 °C) and three short-term heat durations (2, 4, and 6 h) were conducted to test the effects on protein content, the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), and the total antioxidant capacity (T-AOC). The results showed that protein content, antioxidant enzyme activity, and T-AOC in T. urticae were significantly induced by heat stress. These results suggest that heat stress induces oxidative stress and that antioxidant enzymes play an important role in reducing oxidative damage in T. urticae. The data of this study will provide a basis for further research on the molecular mechanisms of thermostability and ecological adaptability of T. urticae.

Codonopsis pilosula is an important Chinese herbal medicine. However, fresh C. pilosula is prone to decay during storage due to microorganism infections, seriously affecting the medicinal value and even causing mycotoxin accumulation. Therefore, it is necessary to study the pathogens present and develop efficient control strategies to mitigate their detrimental effects on the herbs during storage. In this study, fresh C. pilosula was collected from Min County in Gansu Province, China. The natural disease symptoms were observed during different storage stages, and the pathogens causing C. pilosula postharvest decay were isolated from the infected fresh C. pilosula. Morphological and molecular identification were performed, and pathogenicity was tested using Koch’s postulates. In addition, the control of ozone was examined against the isolates and mycotoxin accumulation. The results indicated that the naturally occurring symptom increased progressively with the extension of storage time. The mucor rot caused by Mucor was first observed on day 7, followed by root rot caused by Fusarium on day 14. Blue mold disease caused by Penicillum expansum was detected as the most serious postharvest disease on day 28. Pink rot disease caused by Trichothecium roseum was observed on day 56. Moreover, ozone treatment significantly decreased the development of postharvest disease and inhibited the accumulations of patulin, deoxynivalenol, 15-Acetyl-deoxynivalenol, and HT-2 toxin.

The present study was conducted to evaluate sublethal effects of B-azolemiteacrylic on the two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae). Female adults of T. urticae were exposed to LC₁₀ and LC₃₀ of the acaricide, and the effects on treated females and their offspring were evaluated. The results showed that the fecundity of F₀ female adults treated with LC₁₀ and LC₃₀ of B-azolemiteacrylic was reduced by 30.9 and 39.2%, respectively. Longevity and oviposition period of the females were significantly reduced as well. The developmental duration of egg and deutonymph stage of the F₁ generation were not significantly different from that of the control. The protonymph stage after LC₃₀ treatment lasted significantly longer, whereas the larva, deutonymph and female stage were significantly shorter than the control. The oviposition period of the F₁ generation was significantly shortened, the fecundity of each female decreased significantly, and the ratio of female-to-male was reduced too. Moreover, the average generation period of T. urticae after LC₁₀ and LC₃₀ treatments was shorter than that of the control, and the net production rate (R₀), intrinsic rate of increase (r_m) and finite rate of increase (λ) were all reduced by 33.3, 7.5 and 1.9% (LC₁₀ treatment) and by 51.3, 14.8 and 3.6% (LC₃₀ treatment), respectively. The population doubling time was prolonged by 7.5 and 14.8% after LC₁₀ and LC₃₀ treatments, respectively, compared with the control. These results indicate that B-azolemiteacrylic may effectively inhibit the development rate of the F₀ and F₁ populations of T. urticae, which will help design integrated strategies for the comprehensive control of T. urticae and rational use of pesticides in the field.

Angelica sinensis, a Chinese herbal medicine, is susceptible to molds during storage, reducing its quality, and even generating mycotoxins with toxic effects on human health. Fresh A. sinensis was harvested from Min County of Gansu Province in China and kept at room temperature. Naturally occurring symptoms were observed during different storage stages. Molds were isolated and identified from the diseased A. sinensis using morphological and molecular biology methods. The impact of ozone treatment on postharvest disease development and mycotoxin production was investigated. The results indicated that A. sinensis decay began on day 7 of storage and progressed thereafter. Nine mold species were isolated and characterized: day 7, two Mucormycetes; day 14, Clonostachys rosea; day 21, two Penicillium species and Aspergillus versicolor; day 28, Alternaria alternata and Trichoderma atroviride; and day 49, Fusarium solani. Ozone treatment markedly inhibited the development of postharvest disease and the mycotoxin production (such as, patulin, 15-acetyl-deoxynivalenol, and sterigmatocystin) in the rotten tissue of A. sinensis inoculated with the nine isolates.

To study the physiological mechanisms of Neoseiulus barkeri in response to short-term heat stress, the eggs and the emerged adults were exposed to 38, 40, and 42°C, 85% ± 5%RH,16 h:8 h (L:D) for 2, 4, and 6 h. The activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) as well as the protein content of N. barkeri were examined. All treatments caused significant different changes compared to the untreated control. The protein content increased as the temperature increased, while it showed different changing trends with the prolongation of exposure duration. The enzymatic activity of SOD, CAT, and POD was significantly affected by the temperature treatment. Both the maximum and minimum level of the three enzymes after a short-term heat stress differed significantly to the control group (p < 0.05). The highest values of three enzymatic activities were all obtained at 40°C-4 h. Person correlation analysis indicates that the high temperature was the primary factor affecting the enzymatic activity, while the exposure duration of the heat stress was the secondary factor. In general, the short-term heat stress increased the protein content of Neoseiulus barkeri and up-regulated the expression of SOD, CAT, and POD activities as well.

The predatory miteNeoseiulus barkeri(Acari: Phytoseiidae) is typically used for biocontrol ofTetranychus urticaeon strawberries. However, its biological characteristics are greatly affected by temperature in hot summer days. In this study, the influence of different short‐term heat stresses on the functional response and prey consumption of unmated female ofN. barkerion three stages (egg, protonymph and adult) ofT. urticaewas evaluated. Three temperatures (38, 40 and 42°C), three short‐term heat duration (2, 4 and 6 hr), eight prey densities (3, 6, 9, 12, 15, 18, 21 and 24 individuals), (85 ± 5) % RH and a 16‐hr: 8‐hr (L:D) photoperiod were used during a 24‐hr period in functional response experiments. The results showed that the eggs ofN. barkericould not hatch at 42°C and the type II functional response was determined for adult females ofN. barkeriat all treatments by using the logistic regression analysis. TheN. barkerihad the highest attack rate of 1.029, 2.044 and 0.913 hr^‐1for three stages ofT. urticaeat 25°C and the lowest value of 0.585, 0.973 and 0.498 hr^‐1at 40°C, 6 hr. On the contrary, the handling time of the predator prolonged when the temperature increased from 25°C to 40°C and the maximum level was observed at 40°C, 6 hr (0.126, 0.153 and 0.172 hr). Our study indicated that the effects of short‐term heat stress were negative on the predation ability ofN. barkeriand heat stress should be avoided as much as possible to achieve the best predation and control effect ofN. barkeriin indoor rearing and field release.