Xiaoxue Ji

Managing root-knot nematodes and weeds with 1,3-dichloropropene as an alternative to methyl bromide in cucumber crops in China.

1,3-dichloropropene (1,3-D) was evaluated as a potential alternative for the widely used soil fumigant methyl bromide (MeBr) in cucumber (Cucumis sativus Linn.) crops in China. Six treatments were replicated five times in a randomized complete block design: fumigation with MeBr (400 kg·ha(-1)), three 1,3-D doses (90, 120, and 180 L·ha(-1)), an avermectin dose (7.5 L·ha(-1)), and a nontreated control. Results consistently indicated that MeBr was generally superior to the treatments involving all 1,3-D and avermectin, which in turn were superior to the control, for improving cucumber yield and to control nematode and weed. In two successive seasons, 1,3-D at a dose of 180 L·ha(-1) was as effective as MeBr in increasing plant height, vigor, and yield, as well as showed excellent nematode control efficiency, but it had relatively poor potency to control weeds. The present data support the conclusion that 1,3-D is a promising MeBr alternative for managing nematodes and weeds in cucumber crops and can be used in integrated pest management programs.

Evaluation of 1,3-Dichloropropene as a Methyl Bromide Alternative in Tomato Crops in China

1,3-Dichloropropene (1,3-D, C3H4Cl2) is a potential candidate as a soil disinfectant because of the restriction of methyl bromide (MeBr) in soil fumigation due to its ecological risk. Field trials were conducted to ascertain the efficiency of 1,3-D as a MeBr alternative in tomato ( Solanum lycopersicum L.) and evaluate its application prospects in China. Five treatments were replicated five times in a randomized complete block design: fumigation with MeBr (400 kg ha(-1)), three 1,3-D doses (180, 120, and 90 L ha(-1)), an avermectin dose (7.5 L ha(-1)), and a nontreated control. Results consistently indicated that MeBr was generally superior to the treatments involving all 1,3-D levels and avermectin, which in turn were superior to the control, for improving tomato yield and inhibiting nematode, weed, and mortality caused by plant disease. In both seasons, 1,3-D at the dose of 180 L ha(-1) was as effective as MeBr in increasing plant height, vigor, and tomato yield and in reducing the incidence of soilborne disease, especially in maintaining excellent nematode control efficiency, but it provided relatively poor control over weeds. On the basis of these results, 1,3-D, in combination with other alternatives to MeBr, is recommended to achieve integrated pest management.

Effect of abamectin on root‐knot nematodes and tomato yield

BACKGROUND Tomato growers in Shandong Province, China, commonly face heavy root-knot nematode infestations. Current methods of control include cadusafos and methyl bromide (MeBr), but alternative methods are required because of the high toxicity of these pesticides and the ecological risk of their use. Therefore, abamectin soil applications were evaluated for their potential to control soil nematodes in a series of laboratory tests, greenhouse pot experiments and field trials. RESULTS Laboratory tests showed that abamectin exhibited rapid knockdown of Meloidogyne incognita, with LC(50) and LC(90) values that were superior to those of cadusafos and averaged 7.06 and 21.81 mg L(-1). In the greenhouse pot experiment, soil applications of abamectin provided significant M. incognita control similar to that provided by cadusafos while maintaining excellent plant height and vigour. In the field trials, abamectin exhibited excellent control effects to nematodes while giving a higher tomato yield. There was a 19.3-39.0% yield increase from the various treatments compared with the control, and the best results were obtained from the highest dose of abamectin. CONCLUSION The results of this study demonstrated that abamectin has the potential to be used as an effective alternative to MeBr and cadusafos for nematode control in tomato production in Shandong Province.

Effect of Emamectin Benzoate on Root-Knot Nematodes and Tomato Yield

Southern root-knot nematode (Meloidogyne incognita) is an obligate, sedentary endoparasite of more than 3000 plant species, that causes heavy economic losses and limit the development of protected agriculture of China. As a biological pesticide, emamectin benzoate has effectively prevented lepidopteran pests; however, its efficacy to control M. incognita remains unknown. The purpose of the present study was to test soil application of emamectin benzoate for management of M. incognita in laboratory, greenhouse and field trials. Laboratory results showed that emamectin benzoate exhibited high toxicity to M. incognita, with LC50 and LC90 values 3.59 and 18.20 mg L-1, respectively. In greenhouse tests, emamectin benzoate soil application offered good efficacy against M. incognita while maintaining excellent plant growth. In field trials, emamectin benzoate provided control efficacy against M. incognita and resulted in increased tomato yields. Compared with the untreated control, there was a 36.5% to 81.3% yield increase obtained from all treatments and the highest yield was received from the highest rate of emamectin benzoate. The results confirmed that emamectin benzoate has enormous potential for the control of M. incognita in tomato production in China.

Effect of Abamectin on the Cereal Cyst Nematode (CCN, Heterodera avenae) and Wheat Yield

The cereal cyst nematode (CCN, Heterodera avenae) is a major pest in wheat and until now there is no pesticide registered to control this pest in China. Development of effective methods of controlling CCN is urgently needed. Abamectin is a biological pesticide that has a high nematicide activity. However, the efficacy of abamectin soil application to control CCN in wheat and its effect on yield in China remains unknown. Therefore, laboratory, greenhouse, and field tests were carried out to evaluate the potential of abamectin soil applications for CCN control and improvement of wheat yield. Laboratory tests showed that abamectin exhibited knockdown toxicity to CCN, with LC50 and LC90 values 9.8 and 59.4 mg liter-1. Greenhouse experiment and field trials showed that soil applications of abamectin provided significant CCN control and higher straw dry weights and wheat grain yields. There was an 8.5 to 19.3% yield increase from the various abamectin treatments compared with the control. The results of this study demonstrated that abamectin exhibited a high nematicidal activity to H. avenae and adequate performance to enhance wheat crop yields.

Single basal application of thiacloprid for the integrated management of Meloidogyne incognita and Bemisia tabaci in tomato crops.

Tomato growers commonly face heavy nematode (Meloidogyne incognita) and whitefly (B-biotype Bemisia tabaci) infestations, and previous studies demonstrated that thiacloprid could be used to control M. incognita and B. tabaci in cucumber. However, the efficacy of a single basal application of thiacloprid to control both pests and its effect on yield in tomato remains unknown. In this study, the potential of thiacloprid application to the soil for the integrated control of M. incognita and B. tabaci in tomato was evaluated in the laboratory and the field. Laboratory tests showed that thiacloprid was highly toxic to whitefly adults and eggs with an average lethal concentration 50 (LC50) of 14.7 and 62.2 mg ai L−1, respectively, and the LC50 of thiacloprid for nematode J2s and eggs averaged 36.2 and 70.4 mg ai L−1, respectively. In field trials, when thiacloprid was applied to the soil at 7.5, 15 and 30 kg ha−1 in two consecutive years, whitefly adults decreased by 37.8–75.4% within 60 days of treatment, and the root-galling index was reduced by 31.8–85.2%. Optimum tomato plant growth and maximum yields were observed in the 15 kg ha−1 treatment. The results indicated that a single basal application of thiacloprid could control M. incognita and B. tabaci and enhance tomato growth and yield.