Effects of 1,3-dichloropropene plus chloropicrin on weed seed germination

Telone C-35, a commercial formulation of 1,3-dichloropropene (1,3-D) and chloropicrin (CP), is one of the potential replacements to methyl bromide (MB) for soil fumigation. A laboratory dose–response study and two field trials in tomato were conducted to evaluate their weed control efficacy and their effect on tomato yield. Laboratory studies found that the seeds of Digitaria chinensis were the most sensitive to soil fumigation with Telone C-35, followed by Eleusina indica, Portulaca oleracea and Stellaria media with the LC₅₀ values between 3.35 and 11.68 mg kg⁻¹ soil. Field trials revealed that Telone C-35 applied to the field at 327, 243 and 164 L ha⁻¹ could suppress the percentage of germination weed seeds while maintaining high tomato marketable yields, with no significant differences between MB + CP and the higher two Telone C-35 rates. The yield data from both seasons indicated that all Telone C-35 treatments had a positive effect on tomato yield; there was a 32%–62% increase the mean marketable tomato yield. Our results indicated that Telone C-35 was an excellent MB alternative and could provide acceptable weed control efficacy. Based on our results, Telone C-35, in combination with other alternatives to MB, is recommended to achieve integrated pest management.     

Efficacy of 1,3-dichloropropene plus chloropicrin application methods in combination with pebulate and napropamide in tomato

Small-plot research and large-field validations were conducted to determine the effect of 1,3-dichloropropene (1,3-D)+chloropicrin (Pic) application methods in combination with the herbicides pebulate and napropamide on pest control in fresh market tomato (Lycopersicon esculentum Mill.). In both the small-plot trials and the large-validation fields, various treatments compared the efficacy of soil fumigants and herbicides based on methyl bromide, in-bed and broadcast applications of 1,3-D+Pic, pebulate, and napropamide. The results consistently indicated that either in-bed or broadcast applications of 1,3-D+Pic in combination with pebulate and napropamide are equally effective against the weed Cyperus spp., the nematodes Tylenchorhynchus spp., Belonolaimus longicaudatus, and Meloidogyne spp., and the soilborne disease Fusarium oxysporum f.sp. lycopersici in fresh market tomato. Therefore, broadcast 1,3-D+Pic application can reduce personnel exposure and poisoning risks, without losing pest control efficacy.     

Application of an emulsifiable mixture of 1,3-dichloropropene and chloropicrin against root knot nematodes and soilborne fungi for greenhouse tomatoes in Italy

A mixture of 1,3-dicloropropene 60.5% w/w and chloropicrin 33.3% w/w (Telone C35 EC) may be registered in Italy for soil drip fumigation. Five experiments on greenhouse tomatoes in Northern, Central and Southern Italy compared the effectiveness of this mixture in comparison with methyl bromide to find the optimum application rate in soils infested by Fusarium oxysporum f.sp. lycopersici, F. oxysporum f.sp. radicis lycopersici, Sclerotium rolfsii, Meloidogyne javanica and M. incognita. Its efficacy against F. oxysporum f.sp. radicis lycopersici and M. incognita was confirmed when applied to soils at 100, 200, 300 and 400 l ha⁻¹ (132.4, 268.4, 402.6 and 536.8 kg ha⁻¹) under gas-tight films with 15–45 mm of application water (900–1200 mg Telone C35 EC l⁻¹). In sandy soils, with slight F. radicis lycopersici infections and with heavy nematode (M. incognita) attacks, the mixture, drip applied at 900 mg l⁻¹ during late summer (fumigation: late summer; transplant: late-summer/autumn; last harvest: early spring), performed well up to 132.4 kg ha⁻¹ (100 l ha⁻¹). In sandy loam soils with slight F. radicis lycopersici infections and severe infections of F. lycopersici and galling nematodes (M. javanica), 268.4 kg ha⁻¹ (200 l ha⁻¹) of the mixture applied at 900 mg l⁻¹ as a drip provided yields similar to those of methyl bromide treated plots both in spring and summer cycles. In sandy loam soils, the diseases (F. lycopersici, F. radicis lycopersici) were controlled at rates 268.4 kg ha⁻¹ (containing 90 kg ha⁻¹ of chloropicrin), but the mixture was ineffective against Sclerotium rolfsii occasionally observed in sandy loam soils. In both sandy and sandy loam soils, no significant relationships were found between the rates of mixture applied (132.4, 268.4, 402.6 and 536.8 kg ha⁻¹) and the degree of nematode infestation.     

Effects of emission reduction surface seal treatments on pest control with shank-injected 1,3-dichloropropene and chloropicrin

The phase-out of methyl bromide for preplant soil fumigation has resulted in an increased reliance on combinations of 1,3-dichloropropene and chloropicrin in many annual and perennial cropping systems in California. However, these fumigants also can have negative environmental and human health consequences and considerable research has been conducted on methods to minimize emission of these products from the soil to the atmosphere. To ensure that pest control efficacy is not compromised by emission reduction techniques, this research was conducted to simultaneously evaluate the effects of several surface seal techniques on fumigant emissions and the efficacy of soil-borne pest control with a mixture of 1,3-dichloropropene + chloropicrin. Results indicated that the interaction between emission reduction techniques and pest control efficacy can be complicated. For example in the 2006 trial, some surviving nematodes were observed in plots with both high (manure plus high density polyethylene film) and intermediate (pre-irrigation) 1,3-D cumulative emissions which suggested that emission loses are not solely responsible for some pest control failures. Weed control tended to be better with plastic film treatments and worse with pre-fumigation soil moisture manipulations but was affected less than expected by intermittent water seals. Although pest control clearly was affected by surface seal techniques, especially in shallow soil layers, some differences in nematode and weed control could not be explained solely by surface seals. These results underline the complex interactions among soil moisture and other environmental factors, application techniques, and emission reducing surface seal treatments. As new techniques and technologies become available to reduce fumigant emissions, we recommend that research include pest control efficacy evaluations before any emerging techniques are required by regulators or implemented by growers.     

Management of 1,3-dichloropropene in pineapple for efficacy and reduced volatile losses

Two application methods, single- and double-chisel injection of the fumigant nematicide 1,3-dichloropropene (1,3-D) were evaluated for efficacy and environmental fate in pineapple field experiments. The objectives were to compare the 1,3-D soil distribution between injection methods, evaluate volatile losses to the atmosphere, and to determine efficacy with each method. In a small-plot field experiment, 1,3-D (224, 337, and 393 1 ha⁻¹) was manually injected 30 cm deep with fumiguns to simulate the commercial practice of a single- or double-chisel injection per planting bed. 1,3-D concentrations in the soil atmosphere and in soil samples were determined and compared to nematode control. In two large-scale field experiments, 1,3-D (224 1 ha⁻¹) was applied with commercial injection equipment with and without polyethylene mulch. Air monitoring for 1,3-D showed a reduction in 1,3-D air emissions with single-chisel injection compared with double-chisel injection. In all experiments, the two injection methods resulted in equivalent 1,3-D concentrations in the plant line. Single-chisel injection resulted in improved retention of 1,3-D within the planting bed as shown by low 1,3-D soil concentrations in the interbed. Nematode counts and bioassay studies found equivalent nematode control in the planting bed with either injection method. The single-chisel method, however, resulted in reduced nematode control in the interbed region.     

Efficacy of a new glyphosate formulation for weed control in maize in southwest Nigeria

A field trial in 2003 and 2004 assessed the efficacy of a new formulation of glyphosate, Touchdown Forte HiTech (glyphosate-TF) and two older versions, Roundup (glyphosate-RP) and Touchdown (glyphosate-TD) for weed control in Nigeria. Treatments were glyphosate-TF at 0.25–1.25 kg a.i./ha, glyphosate-RP at 1.8 kg a.i./ha, and glyphosate-TD at 1.0 kg a.i./ha. Weeded and unweeded treatments were controls. Visual evaluations of weed control at 4 and 8 weeks after treatment (WAT) in both years indicated that glyphosate-TF at all doses gave moderate to complete control of all major weeds (50–100%). At 4 WAT, control of Ageratum conyzoides L., Commelina benghalensis L., Ipomoea involucrata P. Beauv., Brachiaria comota [Hochst ex A. Rich] stapf, and Acalypha ciliata Forssk was at a level similar to that in the weeded control. In 2003, all herbicide formulations and the weeded control reduced Imperata cylindrica (L.) Beauv. shoot dry biomass to the same level at 8 WAT (91–100%) and at maize harvest (83–88%). In 2004, 0.50–1.25 kg a.i./ha of glyphosate-TF and 1.8 kg a.i./ha of glyphosate-RP gave 95% reduction at 8 WAT and 97% at harvest, similar to the weeded control. Maize grain yield in the weeded control and herbicide treatments was 2.8 times higher than that in the unweeded control in both years. These results indicate that glyphosate-TF is effective for weed control in maize at herbicide doses lower than the older formulations.     

防治棉花主要害虫的适用农药

棉花种植过程中虫害防治依然是管理的重中之重。做好虫害防治,是棉花产量和质量的重要保障。根据棉田主要害虫种类,分别介绍了适用的防治药剂。     

Effects of the nematicide 1,3-dichloropropene on weed populations and stem canker disease severity in potatoes

The soil fumigant 1,3-dichloropropene (1,3-D) has been used in the UK for the control of potato cyst nematodes (PCN), Globodera pallida (Stone) and Globodera rostochiensis (Wollenweber), but its potential herbicidal activity has not been extensively investigated in this country. Field and glasshouse studies were therefore conducted to evaluate the potential of 1,3-D for the control of weeds in potatoes, and observations were made on the severity of potato stem canker, caused by the fungus Rhizoctonia solani Kühn [teleomorph: Thanatephorus cucumeris (Frank) Donk]. Autumn application of 1,3-D at 211.5 L active substance (a.s.) ha⁻¹ significantly suppressed the number of germinating weeds and the percentage of weed ground cover by 83% and 79%, respectively, relative to controls. There were also species-specific significant decreases (field pansy, Viola arvensis, in particular) in the number of weed seeds germinating in field soil in the glasshouse post-1,3-D treatment. The effect of 1,3-D declined in time and single (autumn or spring) or combined application produced a slight, but not significant, reduction in the number of weeds germinated on potato ridges relative to those recorded in untreated soil. The severity of stem canker on potato plants was not significantly reduced by 1,3-D but both mean number and weight of stems per plant were significantly increased compared with plants from untreated plots. These studies demonstrated that 1,3-D, in addition to giving PCN control, has efficacy against weeds; implications are the potential for reduced herbicide input in the crop rotation with accompanying economic and environmental benefits.     

Pheromones for the control of insect pests in Mediterranean countries

Pheromones can be used to monitor insect populations or to control directly certain pest species by mass-trapping or mating-disruption techniques. The potential advantages of using pheromones for crop protection in these various ways are illustrated by examples taken mainly from work conducted in the Mediterranean region by members of the Scientific Units of the Overseas Development Administration.     

茶园主要害虫无害化防治技术

2009年,农业部在全国范围内启动了蔬菜、水果、茶叶等园艺作物标准园创建工作,第一批创建园艺作物标准园819个,其中蔬菜401个、水果300个、茶叶118个。园艺作物标准园创建工作的重点是探索在园艺作物生产中建立生态栽培体系,采用病虫无害化防治技术,达到减少化学农药使用,保障园艺产品食用安全,保护生态环境的目的,促进园艺产业增效和园农增收。     

茶树害虫防治的新途径--化学生态防治

本文介绍了应用化学生态学原理进行茶树害虫防治的目前进展和发展前景。重点介绍了应用昆虫性信息素和茶树挥发性互利素在害虫防治中的应用。在昆虫性信息素的应用上,主要利用人工模拟的雌性害虫的性信息素来引诱同种害虫的雄性害虫以达到预测和迷向防治的目的。在茶树挥发性互利素的应用上,当害虫危害茶树后,害虫的口腔分泌物中的酶类会由叶片的伤口进入茶树组织内而使茶树体内代谢途径发生变化,形成新的挥发性化合物。这种新的挥发性化合物对这些害虫的天敌有很强的引诱作用,而对害虫却没有或只有很弱的引诱活性,通过这类化合物可以使天敌很容易找到它扑食或寄生的害虫的位置,为天敌寻觅到害虫提供了线索,同时为被害的茶树提供了保护．应用化学生态学进行害虫的防治尽管还没有在生产上达到应用的程度,但前景辉煌。     

Efficacy of chloropicrin application by drip irrigation in controlling the soil-borne diseases of greenhouse pepper on commercial farms in Poland

Three demonstration experiments were conducted on commercial greenhouse farms to assess the efficacy of chloropicrin (CP), applied by drip irrigation, in controlling Verticillium wilt and root rot disease complex of bell pepper, in comparison with dazomet at 40 g m⁻². Chloropicrin was applied through drip irrigation system at 20, 30 and 40 g m⁻² of emulsified commercial formulation. The concentration of CP in water was constant, and the required doses were obtained by delivering different amounts of the irrigation water per area unit (from 12.5 to 33 mm). The highest mean efficacy in reducing the inoculum density of Verticillium dahliae in the soil at all locations was obtained after CP application at 30 and 40 g m⁻², about 85 and 86%, respectively. The number of viable microsclerotia recovered from the soil on the day of pepper planting was significantly correlated with the final incidence of Verticillium wilt disease (r = 0.962). The highest mean efficacy in controlling Verticillium wilt of pepper (86.4%) was obtained after soil treatment with CP at 40 g m⁻², and ranged from 80.2 to 95.6%. The yield was stronger correlated with root rot severity (r = −0.849**) than with progression of Verticillium wilt, expressed by AUDPC (r = −0.651**). The dominant soil-borne pathogen responsible for pepper root rot was Colletotrichum coccodes. All chemical treatments provided a significant reduction in root rot severity compared to the untreated control. On-thefarm evaluation revealed that soil fumigation with drip-applied chloropicrin presents a feasible option for pepper growers.     

大豆地下害虫生物生态控制

针对大豆一般地下害虫为害特点、主要种类生活习性,采取相应的生物生态控制策略进行归纳总结,充分利用自然资源———植物源农药、昆虫病原微生物、天敌进行生物防治,利用生态措施对大豆地下害虫进行控制,为大豆生产实践提供参考。     

Resolving economic decisions for the simultaneous control of two pests,diseases or weeds

Models are presented that show how to derive economic thresholds and to optimize pesticide treatment rates for situations in which two pests coincide. A hypothetical example using a tank-mix of chlorpyrifos and MCPA to control leatherjackets and Viola arvensis in spring barley is presented. This demonstrates the effective lowering of thresholds as a result of reducing fixed costs of application. It is suggested that the models can be extended into n dimensions and that this will acoomodate n−1 pests.     

Cowpea seed treatment with carbosulfan: potential for control of seedling pests

Results from three field trials and a screenhouse study conducted in 1985 and 1986 using carbosulfan (Marshal 25 ST) insecticide dust formulation at 0, 10, 20, 30 and 40 g/kg cowpea seed indicated that infestation and/or damage by aphids, foliage beetles and leafhoppers was satisfactorily reduced with treatment levels above 20 g carbosulfan/kg seed. The period of activity of the different treatments ranged from 15 to 23 days for various pests in the screenhouse, and slightly longer in field trials. Post-flowering pests were, however, not controlled at any of the rates tested. The ease of application and high dermal LD₅₀ (> 2000 mg/kg rabbit) make Marshal 25 ST a very attractive option for use by small-scale farmers as a component of an integrated pest management strategy in locations where these pests are important and adequate levels of genetic resistance are not available.     

Combining residues of herb crops with soil heating for control of soilborne pathogens in a controlled laboratory system

Plant residues from herb crops were examined as organic amendments for the control of soilborne pathogens with and without soil heating for a short exposure of 2 weeks. Residues of herbaceous plants of oregano, sage, rosemary, tarragon, bay, wild rocket, spearmint and thyme were incubated for 14 days in a controlled laboratory system which emulates soil solarization. Green cabbage residues were included for comparison. The tested pathogens included Fusarium oxysporum f. sp. radicis-lycopersici, Macrophomina phaseolina, Rhizoctonia solani and Meloidogyne javanica. Heating soil amended with herb residues, particularly tarragon, spearmint and wild rocket, resulted in high mortality of the tested pathogens. Volatile compounds which were generated in heated soils amended with wild rocket or tarragon showed significant toxicity to M. phaseolina and R. solani. Only oregano, thyme, bay, wild rocket and tarragon amendments were effective in pathogen control without heating. Incorporation of leaf and stem residues of thyme, sage, tarragon, rosemary or wild rocket in soil and exposure to solarization under field conditions resulted in 95-100% mortality of the tested pathogen. This study demonstrates that the residues from herb crop production can serve as organic amendments for the control of soilborne pathogens, especially when combined with heating or solarization.