First Record of Fusarium verticillioides as an Entomopathogenic Fungus of Grasshoppers

Fusarium verticillioides (Saccardo) Nirenberg (Ascomycota: Hypocreales) is the most common fungus reported on infected corn kernels and vegetative tissues, but has not yet been documented as being entomopathogenic for grasshoppers. Grasshoppers and locusts represent a large group of insects that cause economic damage to forage and crops. Tropidacris collaris (Stoll) (Orthoptera: Acridoidea: Romaleidae) is a large and voracious grasshopper that in recent years has become an increasingly recurrent and widespread pest in progressively more greatly extended areas of some of in Argentina's northern provinces, with chemical insecticides being currently the only means of control. During February and March of 2008–09, nymphs and adults of T. collaris were collected with sweep nets in dense woodland vegetation at a site near Tres Estacas in western Chaco Province, Argentina, and kept in screened cages. F. verticillioides was isolated from insects that died within 10 days and was cultured in PGA medium. Pathogenicity tests were conducted and positive results recorded. Using traditional and molecular-biological methods, an isolate of F. verticillioides was obtained from T. collaris, and its pathogenecity in the laboratory was shown against another harmful grasshopper, Ronderosia bergi (Stål) (Acridoidea: Acrididae: Melanoplinae). The mortality caused by F. verticillioides on R. bergi reached 58 ± 6.53% by 10 days after inoculation. This is the first record of natural infection caused by F. verticillioides in grasshoppers

Extracts and phenolic compounds from Zuccagnia punctata as fungicide seed protectants for corn

The ethanolic leaf extract (TZP) of Zuccagnia punctata, its ethereal fraction (Eet), 2′,4′-dihydroxychalcone (DC), 2′,4′-dihydroxy-3′-methoxychalcone (DMC) and 7-hydroxy-3′,4′-dimethoxyflavone (HF) were evaluated as fungicide seed protectants on corn. Microdilution assays on a set of Fusarium strains showed minimum inhibitory concentrations (MICs) of 400–800 μg mL−1 (TZP), 50–100 μg mL−1 (Eet), 25–50 μg mL−1 (DC), 50–100 μg mL−1 (DMC) and 200–400 μg mL−1 (HF), with minimum fungicidal concentration (MFC)/MIC = 1. Suspensions of TZP, Eet, DC and DMC at MIC × 20 incorporated to the grains at rates of 1920, 240, 120 and 240 mg dry matter kg−1 of grain, respectively, increased the elongation of the primary roots (24–44%) and the number of seminal roots (44–50%). TZP also increased the number of secondary roots. HF was phytotoxic. Suspensions of TZP, Eet, DC and DMC suppressed the endogenous grain mycoflora at levels similar to those recorded for a thiram + carbendazim-based fungicide. Grains treated with TZP (1920 mg kg−1), Eet (240 mg kg−1), DC (120 mg kg−1) and DMC (240 mg kg−1) stimulated the growth of the seedling root system both because of fungal suppression and hormetic effects in greenhouse curative and preventive assays against Fusarium verticillioides on a sand/soil substrate. Eet and its chalcones also reduced the severity of seedling blight more than the thiram + carbendazim-based fungicide in preventive assays and led to the same disease severity observed for the fungicide treatment in the curative assays. Our results show that Eet and its chalcones not only were effective seed protectants against F. verticillioides and other seedborne fungi, but also improved the early performance of maize seedlings.Fil: Jiménez, Cristina Marisol. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Estudios Vegetales. Cátedra de Fitoquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; ArgentinaFil: Sgariglia, Melina Araceli. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Estudios Vegetales. Cátedra de Fitoquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; ArgentinaFil: Soberon, Jose Rodolfo. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Estudios Vegetales. Cátedra de Fitoquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; ArgentinaFil: Vattuone, M.A.. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Sampietro, Diego Alejandro. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Estudios Vegetales. Cátedra de Fitoquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentin