Potential of Deploying Indigenous Fungi in the Management of Potato Cyst Nematodes (Globodera Spp.) on Potato in Nyandarua County, Kenya
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Date
2021
Authors
Musango, Jane Kavenya
Journal Title
Journal ISSN
Volume Title
Publisher
Kenyatta University
Abstract
In Kenya, the second important food crop after maize is potato Solanum tuberosum
L. whose production is severely constrained by inadequate certified seeds, pests
and diseases. Among the pests, potato cyst nematodes (PCN) are the major plant
parasitic nematodes. The objective of this study was to enhance potato production
by developing an effective management option for PCN through adoption of
indigenous fungi in Kenya. Soil samples were collected from potato growing areas
in Nyandarua, Nakuru, Meru, Nyeri, Kericho, Nandi, Kiambu and Bungoma
Counties between March and May 2017 for cyst extraction. The In vitro tests and
greenhouse experiment were conducted at Kenyatta University and field
experiments at Kwa Haraka and Engineer in Nyandarua County. Field experiments
were conducted between June 2018 and February 2019 while greenhouse was
conducted between December 2018 and July 2019. Completely randomized design
was used for laboratory and greenhouse experiment while randomized complete
block design was used for field experiment in 4 replicates. Fungi were isolated
from cysts of PCN by plating them on Potato Dextrose Agar and their effect on
juvenile mortality determined. Trichoderma atroviride, T. atrobrunneum, T.
tomentosum 1 and 2, bionematon and control were used as treatments in
greenhouse and field experiments. Treatments were applied by soil drenching at
planting, 30 and 60 days after planting. Data on plant height, root length, dry root
and shoot weight, potato yield and nematode population were determined in vivo.
Data was analyzed using Analysis of Variance with SAS version 9.2. Means were
separated using Fisher’s Least Significance Difference at P≤0.05. Eighty fungal
isolates from nine genera were isolated from cysts and there was a significant
(P<0.05) difference among the isolates on juvenile mortality. Juveniles treated
with P. lilacinum, T. atroviride T. tomentosum 1, T. tomentosum 2 and T.
atrobrunneum revealed highest mortality rates of 98-100 %. All fungal isolates
significantly enhanced potato growth and yield and reduced nematode population
compared to the control in the greenhouse and field. Fungal isolates reduced
juvenile population by 6- 43% and 9- 39% under field conditions in Kwa Haraka
and Engineer sites, respectively. In the control, an increase of 80- 104% in juvenile
population was recorded. Trichoderma tomentosum 2 and T. atroviride recorded
the least PCN reproduction factor of 0.4- 0.7 while the untreated control recorded
the highest of 1.8-2.4 in the field. Trichoderma atroviride and T. tomentosum 2
signficantly increased yield by 200% -900% in the field and 46- 58% in the
greenhouse. Trichoderma atroviride and T. tomentosum 2 were the most effective
in reducing PCN populations hence should be formulated and commercialized for
their management.
Description
A thesis submitted in partial fulfillment of the requirement for the degree of Master of Science in Crop Protection (Plant Pathology) in the School of Agriculture and Enterprise Development, Kenyatta University, September, 2021
Keywords
Potential, Deploying Indigenous Fungi, Management, Potato Cyst Nematodes (Globodera Spp.), Potato, Nyandarua County, Kenya