Management of maize lethal necrosis disease through hand weeding and insecticide applications at Arba Minch in Southern Ethiopia

Abstract

Maize lethal necrosis (MLN) is considered an important constraint of maize production in Ethiopia and particularly in southern part of the country. The study was conducted during 2016 and 2017 main cropping seasons to (i) determine the effect of hand weeding and insecticide application against MLN and yield and yield related attributes of maize; and (ii) to determine the economy of additional costs used for the management of MNL. The treatments such as hand weeding, only insecticide applied, hand weeding in combination of insecticide application (HW + InA) and unmanaged were arranged in randomized complete block design with five replications. Results showed that MLN severity was highly significant (p < 0.001) different both during 2016 and 2017 cropping seasons. It was varied among the treatments and between cropping years. In the two years, it was highest on unmanaged plots with 66.33% in 2016 and 56.33% in 2017. This might have been due to severe insect and weed infestation during the growing period over the evaluated plots. Conversely, the lowest MLN severity was recorded on the HW + InA with the value of 26.67% in 2016 and 25.00% in 2017 cropping season. Thus, severity was reduced by 62.31% in 2016, and 52.65% in 2017 in this treatment. As such not much difference in the area under disease progress curve (AUDPC) was observed in the two years. However, in both cropping seasons the lowest (15.96% and 15.01%-days, respectively) mean amount of AUDPC was recorded from plots managed with HW + InA. In 2016 and 2017 cropping seasons, HW + InA proved to be an effective against MLN management and gave the highest yields (4.89 and 5.84 t ha⁻¹, respectively) over the unmanaged (1.06 and 1.39 t ha⁻¹, respectively). Overall, results showed HW + InA was found to be better management option and reduced MLN and increased grain yields. Thus, it is better, as compared to other treatments, to use management option as it gave the relatively higher defense against MLN. However, further studies have to be undertaken in different agro-ecologies elsewhere in Ethiopia for developing solid advice on behalf of stabilizing maize production. Moreover, further research is warranted to confirm the role of insect pests and weeds as vector and alternative hosts, respectively for MCMV, SCMV, MDMV and WSMV causing MLN.

Keywords:

• AUDPC
• insecticide
• insect
• MLN
• hand weeding
• severity
• weed

PUBLIC INTEREST STATEMENT

Maize lethal necrosis (MLN) is an emerging disease and major threatening disease of maize production systems in eastern and central Africa. The MLN is a serious challenge in major maize producing areas of Ethiopia. Since the outbreak, it causes considerable yield losses. However, lack of awareness about the role of unwise managements, insect vectors transmission and loaded on alternate hosts by the growers and less attention by the experts to virus diseases become a serious problem to many parts of the country, which demands an urgent reply from stakeholders. To recommend, managing of insect vectors and alternate hosts that influence the MLN intensity is a prerequisite. In this study, therefore, different management approaches in combination or alone have been studied. Thus, the results recommended using insecticide along with hand weeding as it gave relatively higher defense against MLN that target on the insect vectors and alternate hosts.

Competing interests

The authors declare no competing interests.

Acknowledgements

The authors would like to acknowledge Southern Agricultural Research Institute, SARI, Ethiopia, for financing and providing all the necessary facilities to the study. We express our heartfelt appreciation and gratitude to our staff members at Arba Minch Agricultural Research Center for their assistance in providing us technical support and data collection. We are very thankful to Habtamu Terefe (PhD) (Haramaya University, School of plant science) and Gediyon Tamiru (MSc) (Hawasa Agricultural Research Center, SARI) who helped us in one way or another for the accomplishment of this study.

Additional information

Funding

The authors received no direct funding for this research.

Notes on contributors

Getachew Gudero Mengesha

Getachew Gudero Mengesha (MSc, BSc) is a plant pathology researcher and staff of the Arba Minch Agricultural Research Center of Southern Agricultural Research Institute, Ethiopia. He has experienced in conducting field experiments in different crops in collaboration with colleagues and alone. He has also experienced in undertaking a comprehensive field survey studies to understand the interaction and association of different biophysical factors to decrease or increase plant disease epidemics. Currently, he has designed and carried out many epidemiological studies under both controlled and natural conditions. He takes account for integrated disease management option and recommend subsistence farmers and private owners who involved in crop production systems to exploit the integrated management option to manage the plant diseases and keep going the productivity of the crops. He is involved in regional, national and international projects focusing on crop protection and production systems in collaboration with colleagues and alone.