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316856

Residual toxicity of Methomyl and γ-Cyhalothrin against Papaya mealybugs on Cassava Leaves

Article

Last updated: 04 Jan 2025

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Abstract

  Paracoccos marginatus Williams and Granara de Willink (P. marginatus or papaya mealybugs [PMBs]) is responsible for 75% of the estimated economic loss in cassava growing worldwide. Insecticidal formulations have the ability to manage P. marginatus by deteriorating its wax coats to death; nevertheless, it has received little attention in the the tropical setting. In the present study, we investigated the residual toxicity of methomyl and γ- cyhalothrin against papaya mealybugs (PMBs) (Paracoccos marginatus) in cassava (Manihut esculenta) leaves and determined what stage in the PMB's life cycle the pest is killed by the chemical. Using the label recommendation rate, each insecticide was sprayed onto the surface of healthy leaves of cassava plants. Leaf samples were taken after  a period of 2 days from a previously sprayed cassava plant.  Using leaf dipping bioassay, cassava leaf samples were cut into circular disc and placed in petri dish lined with wet filter paper, and 20 crawlers, 20 pre-adults, and 20 adult PMBs were introduced into each dish.. The The preparation was under controlled conditions of temperature, relative humidity and photoperiod (25°C; 80% RH; 12h light: 12h dark) in the laboratory and the number of dead insects was recorded. Each group was replicated in three replicates for each stage of the pest's life and for each insecticide tested. Results showed that crawlers were the most susceptible to both insecticides studied. For the residual toxicity test, the half- life of methomyl is 5.1 days while that of γ-cyhalothrin is 4.7 days. These findings suggest that farmers have to wait 5.1 and 4.7 days, respectively for their next spray application schedule.  Furthermore, as part of food safety measures, when fresh cassava leaves are used as human food and animal feed, the waiting time for the insecticides to dissipate from the leaf surface is the same as previously stated.

DOI

10.21608/ejar.2023.210536.1404

Keywords

agriculture, Insecticides, leaf dip bioassay, toxicity test

Authors

First Name

Elena

Last Name

Lozano

MiddleName

B.

Affiliation

Cebu Normal University, Osmeña Boulevard, Cebu City, Philippines 6000

Email

lozanoe@cnu.edu.ph

City

CEBU CITY

Orcid

-

First Name

Jake Joshua

Last Name

Garces

MiddleName

-

Affiliation

Cebu Normal University, Osmeña Boulevard, Cebu City, Philippines 6000

Email

garcesjj@cnu.edu.ph

City

CEBU CITY

Orcid

0000-0003-1080-0557

First Name

Erlinda

Last Name

Vasquez

MiddleName

A.

Affiliation

College of Agriculture and Food Sciences, Department of Pest Management, Visayas State University, Baybay City, Leyte 6521-A PhilRootCrops, Philippine Root Crop Research and Training Center, Visayas State University, Baybay City, Leyte 6521-A

Email

erlinda.vasquez@vsu.edu.ph

City

Baybay City, Leyte

Orcid

-

Volume

102

Article Issue

2

Related Issue

47121

Issue Date

2024-07-01

Receive Date

2023-05-12

Publish Date

2024-04-18

Page Start

197

Page End

207

Print ISSN

1110-6336

Online ISSN

2812-4936

Link

https://ejar.journals.ekb.eg/article_316856.html

Detail API

https://ejar.journals.ekb.eg/service?article_code=316856

Order

2

Type

Original Article

Type Code

1,041

Publication Type

Journal

Publication Title

Egyptian Journal of Agricultural Research

Publication Link

https://ejar.journals.ekb.eg/

MainTitle

Residual toxicity of Methomyl and γ-Cyhalothrin against Papaya mealybugs on Cassava Leaves

Details

Type

Article

Created At

24 Dec 2024