Effect of neem on Phyllocnistis citrella Stainton and its parasitoid Ageniaspis citricola Logvinovskaya in Ecuador

Ernesto Cañarte-Bermúdez,Néstor Bautista-Martínez,Onésimo Chávez-López,Hugo César Arredondo-Bernal,Silvia Montero-Cedeño,Bernardo Navarrete-Cedeño

doi:10.29019/enfoque.v11n2.519

Abstract

Efficacy of neem on Citrus Leafminer (CLM) and effect on its parasitoid Ageniaspis citricola was evaluated, using field, cage and olfactometer tests. Treatments were: aqueous extract of neem (50 gL-1), formulated oil of neem (10 mL L-1) and control. Field study was done in a Citrus aurantifolia orchard, three applications were carried out, which were evaluated every 48 hours until ten days after the treatment. Cage and olfactometer tests were performed in a greenhouse and repeated twice each time. In the cage, it were used 50 infested Citrus reticulata plants per experimental unit, while for the olfactometer test, as experimental arena, transparent plastic jars with 20 adults of CLM inside were used. Variables evaluated were: CLM infestation, dead, live and predated larvae, pupae, emerged adults and parasitized pupal chambers. The highest mortality of the CLM was caused by the aqueous extract of neem with 77.17%, which began 48 hours after application, suggesting inhibition of feeding. The aqueous extract of neem showed in average 88.80 % of repellency of adults of CLM and neem oil 85.64%. The high mortality of CLM and the repellent effect of neem, seem to influence negatively in parasitism which fluctuated between 9.45 % and 20.16 % in treated trees.

Highlights

The Citrus Leafminer (CLM) Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae), is an important pest of citrus, native from southern Asia, but today widespread in several countries producers of citrus in America, Africa, Europe and Oceania (Beattie and Hardy, 2004, Sarada et al, 2014)
Larval mortality was determined visually in the field, using an OptiVisor TM magnifier glass (4x) and applying the formula cited by Tierto (1994): The effect of neem on parasitism was determined based on the following variables: live larvae, dead larvae, adults emerged from CLM and pupa with evidence of parasitism, obtaining the percentage of parasitism in each evaluation, by the formula cited by Castaño (1996): This experiment was repeated three times during the dry season
It is observed that statistically the aqueous extract differs from the other two treatments, presenting the lowest infestation (11.97%), followed by the neem oil formulated with 18.41%

Summary

Introduction

The Citrus Leafminer (CLM) Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae), is an important pest of citrus, native from southern Asia, but today widespread in several countries producers of citrus in America, Africa, Europe and Oceania (Beattie and Hardy, 2004, Sarada et al, 2014). As an indirect damage the lesions caused by CLM can facilitate the infection of bacterial diseases as the citrus canker Xanthomonas axonopodis pv. Nowadays is present in the main citrus producer zones of the country, that means that close to 10 000 ha of citrus orchards are in potential risk due to the presence of the pest. Estimations of losses in Citrus aurantifolia reach the 45 % and the higher rate of infestation is close to 100 % (Valarezo and Cañarte 1998, Valarezo et al, 2004)

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Results

Conclusion