New biological product to replace methyl bromide
Specialists at the Genetic Engineering and Biotechnology Centre (CIGB) in Camagüey, Cuba, have developed a biological nematicide that, without any secondary effects, interrupts the reproductive cycle of crop-damaging worms. The active agent in HeberNem is Tsukamurella paurometabola, strain C-924. This bacteria has demonstrated the best efficiency among the 158 strains analysed.


This is the first time that the antiparasitical and nematicidal functions of the micro-organism have been established, for which the product has already received two national patents and has also been approved by international patent agencies in several European, American and Asian countries. In places with harsh winters, it is customary to disinfect the soil with methyl bromide (MB). However, owing to the damage this chemical causes to the ozone layer and because other chemicals applied as substitutes have equally undesirable effects, the world has been painstakingly searching for organic solutions. HeberNem has the potential to take the place of MB.


Tsukamurella paurometabola, a naturally occurring micro-organism, is found in soil and organic matter. This strain can be isolated and conserved in cell banks, which can then be reproduced on a large scale. Despite the fact that all of this occurs in an invisible world, HeberNem has demonstrated an “enormous” capacity to reduce the presence of nematodes, thus increasing agricultural yields. It has been tested on more than 25 ha of distinct soil types and, after 18 toxicological and ecological tests, the nematicide has demonstrated to be an innocuous product without any type of negative environmental effects.


HeberNem has exhibited an efficiency rate of 90-95 per cent. In several citrus companies throughout the country (La Jíquima in Holguín; Ceballos in Ciego de Avila; Arimao in Cienfuegos; Jagüey Grande in Matanzas, and Cítricos Sola and Los Ranchos in Camagüey, among others) HeberNem has been used with successful results.


Website: www.granma.cu
Controlling weeds
In the United States, a team of researchers from Alabama Agricultural Experiment Station and the Auburn University investigated into the efficacy of various combinations of furfural (2-furfuraldehyde) with metam sodium and dazomet in weed control. Furfural is a naturally occurring compound produced commercially from sugar cane bagasse and other pentosan containing materials. This compound has significant nematicidal properties, with limited activity against some weed species. Mixtures of furfural with methyl isothiocyanate and methyl isothiocyanate-generating compounds (metam sodium and dazomet) were studied as broad-spectrum treatments to replace methyl bromide in soil fumigation.


In trials, metam sodium and furfural were applied to soil at rates of 0-500 mg ai/kg soil alone and in combination with metam sodium at 19.6 mg ai/kg soil. The soil (from a cotton field) used in these trials was infested with yellow nutsedge, large crabgrass, hybrid pigweed, annual morningglory and other annual weeds. In another set of experiments, furfural and dazomet were delivered in an aqueous emulsion containing 8 per cent furfural and 2 per cent dazomet. Results from the studies reveal that combinations of furfural with either metam sodium or dazomet exhibit strong herbicidal activities derived from synergistic interactions between furfural and the other compounds.


Contact: Mr. R. Rodriguez Kabana, The Auburn University, the United States.


E-mail: rrodrigu@accesag.auburn.edu 


Website: www.mbao.org
Efficacy of MB alternatives on tomato crops

In the United States, researchers at North Carolina State University, have studied the efficacy of fall and spring applied methyl bromide (MB) alternatives on Amelia variety of tomato. Results have shown that application of InLine in the spring yielded superior yields compared to MB applied in the fall and similar to MB in spring. Similarly, Telone-C25 generated yields comparable with the respective MB treatments. Phytotoxicity was not recorded consistently for any treatment. A 14-day plant-back waiting period was adequate to avoid Telone-generated phytotoxicity. Contact: Mr. R. M. Welker, Department of Plant Pathology, North Carolina State University, Raleigh, NC 27695, United States of America.


Website: www.mbao.org 

Mulch effect on nutsedge control
Researchers at the University of Florida, the United States, have studied the efficacy of mulches in an integrated pest management programme to lower the use of hazardous fumigants like methyl bromide. In two field studies, metallized, HDPE mulches and virtually impermeable film (VIF) were used with methyl bromide (MB) and chloropicrin. In these trials, VIF and metallized mulch had higher MB concentrations in the soil than HDPE. However, differences between VIF and metallized mulch were not consistent throughout the two trials. Increasing fumigant rates raised nutsedge control for each mulch. Nutsedges were controlled the best with metallized mulch.


Website: www.mbao.org
Weed control using sodium azide and herbicides
In the United States, researchers at the Auburn University and Alabama Agricultural Experiment Station have tested the efficacy of using sodium azide in combination with commercially available herbicides to control weeds. Sodium azide, in its SEP 100® (American Pacific Corp.) formulation, controls plant pathogenic nematodes and fungi when applied to soil at rates less than 44.8 kg ai/ha. Combinations of sodium azide with three registered herbicides, which are effective against nutsedges and other hard-to-kill weeds, were investigated. Soil used for the trials was infested with yellow nutsedge, hybrid pigweed, large crabgrass, morning glory and other annual weeds.


Results unveil that after 28 days of treatment, SEP 100 alone at 44.8 kg/ha rate was ineffective in controlling nutsedge. However, all combinations of SEP 100 with s-metholachlor yielded excellent control of nutsedge and other weed species. After 32 days of treatment, wherein SEP 100 had been applied at 0 and 44.8 kg ai/ha alone as well as in combination with halosulphuron-methyl at 10.2, 25.4, 50.8, 88.9 and 101.6 g ai/ha, combination treatments of SEP 100 and halosulphuron-methyl resulted in excellent nutsedge control and the best overall herbicidal activity.


Contact: Mr. R. Rodriguez Kabana, Auburn University, United States of America.


E-mail: rrodrigu@accesag.auburn.edu


Website: www.mbao.org
MB alternatives for strawberry
Researchers at Instituto Andaluz de Investigacion y Formacion Agraria, Spain, and IFAS-University of Florida, the United States, have evaluated some methyl bromide (MB) alternatives for application on strawberry. Experiments were undertaken at two sites, one in Spain and the other in Florida. Common treatments in both locations were non-treated control, MB + chloropicrin, 1,3-dichloropropene + Pic (Telone C-35 and Telopic), Pic, dimethyl disulphide (DMDS) + Pic and propylene oxide (Propozone). Dazomet was only tested in Spain, whereas the combination of methyl iodide + Pic was used in Florida. Results have unveiled that Telone C-35, DMDS + Pic and Pic consistently exhibited similar marketable yields as MB + Pic. Similar results were found in Florida, with the exception of propylene oxide, which had equal marketable fruit weight as MB + Pic.


Website: www.mbao.org