Document Type

Thesis - Open Access

Award Date

2020

Degree Name

Master of Science (MS)

Department / School

Agronomy, Horticulture, and Plant Science

First Advisor

Emmanuel Byamukama

Keywords

management, nematicides, Plant extracts, Soybean Cyst Nematode (SCN)

Abstract

Soybean cyst nematode (SCN) is a microscopic worm that infects and feeds from the soybean roots, hence robbing the plant of nutrients, and entry wounds may facilitate other pathogens to infect the roots. Current SCN management practices include cultural, chemical, and biological methods. Cultural practices such as, crop rotation with non-host and different tillage practices are not efficient due to the persistent nature of SCN in the soil. Chemical nematicides, though effective, can be expensive, and some are not environmentally sound. SCN resistant soybean varieties are mainly derived from one source, PI 88788 and SCN population have already evolved to overcome this resistance. Plant extracts can be a safe and sustainable alternative for SCN management. This study tested the aqueous extracts from dry leaves and flowers of ragweed (Ambrosia artemisiifolia) and wormwood (Artemesia absinthium), and dry leaves of leafy spurge (Euphorbia esula) on SCN egg hatching and second stage juvenile (J2) mortality under laboratory and cysts development on soybean in greenhouse conditions. All the plant extracts at 5mg/ml inhibited the hatching by more than 90%. Among the plant extracts tested, ragweed dry flower at the rate of 94 mg/ml, caused 100% J2 mortality at 84 hours after application of extract. Plant extracts of wormwood dry flower dry leaf of ragweed, wormwood, and leafy spurge at 94 mg/ml caused 90.5%, 89.4%, 86.6%, and 57.2% J2 mortality, respectively. In greenhouse test, soybean cyst nematode susceptible cultivar Williams 82 was grown on the soil from the SCN infested field and treated with 75 ml of extract per plant. Tap water was used as negative control and ILeVO nematicide seed treatment was used as positive control. Ragweed dry flower and dry leaf at the concentration of 100 mg/ml reduced the SCN cyst per gram of root as effectively as ILeVO nematicide seed treatment. These findings will be helpful in further developing and testing of plant based nematicides. wormwood, and leafy spurge at 94 mg/ml caused 90.5%, 89.4%, 86.6%, and 57.2% J2 mortality, respectively. In greenhouse test, soybean cyst nematode susceptible cultivar Williams 82 was grown on the soil from the SCN infested field and treated with 75 ml of extract per plant. Tap water was used as negative control and ILeVO nematicide seed treatment was used as positive control. Ragweed dry flower and dry leaf at the concentration of 100 mg/ml reduced the SCN cyst per gram of root as effectively as ILeVO nematicide seed treatment. These findings will be helpful in further developing and testing of plant based nematicides.

Library of Congress Subject Headings

Soybean cyst nematode -- Control.
Nematocides.
Soybean -- Diseases and pests.
Plant extracts.

Format

application/pdf

Number of Pages

116

Publisher

South Dakota State University

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Rights Statement

In Copyright