Sciarid pests (Diptera: Sciaridae) from undercover crop production in South Africa
Date
2020-03-26
Journal Title
Journal ISSN
Volume Title
Publisher
Academy of Science of South Africa
Abstract
Fungus gnats (sciarids) are among the most important pests in undercover crop production. They cause
direct physical damage to plant roots, transfer fungal pathogens and create entry points for soil-borne plant
pathogens. In 2007, Bradysia impatiens, an important fungus gnat pest was found in association with major
tree nursery beds in the Mpumalanga and KwaZulu-Natal Provinces of South Africa and was considered
invasive. In this study, eight greenhouses were surveyed in the Western Cape Province and B. impatiens was
found to be present in all the greenhouses. Similar to the results of the previous studies, a high haplotype
diversity was identified for B. impatiens, which may indicate multiple strain introductions into South Africa.
Two other fungus gnat species, Lycoriella sativae and Lycoriella ingenua – globally important sciarid pests of
mushroom cultures – were identified as new from South Africa. Through a laboratory culture, the life cycle of
B. impatiens was observed to be approximately 21 days at 25 °C. Females laid between 100 and 250 eggs.
Possible introduction sources include contaminated vegetative material and growth media, thus there maybe
need to revise the importation restrictions on these commodities. The identification of two novel species of
sciarid pests that have only previously been identified in the Holarctic region could further emphasise this
need. However, the recent discovery of such high sciarid diversity could also be due to only a few studies
having been previously done on sciarid pests in South Africa.
Significance:
• The fungus gnat species Bradysia impatiens is reported as present in several undercover crops in
the Western Cape Province of South Africa, including cucumbers, tomatoes, chrysanthemums,
mushrooms, blueberries and various herbs.
• Lycoriella ingenua and Lycoriella sativae were also found to be present in mushroom gardens – the first
report of Lycoriella from the Afro-tropical region.
• The three fungus gnat species are some of the most important sciarid pests in undercover crop
production worldwide. This study highlights the need for more studies on the distribution of these
sciarids and possible invasion history.
Description
CITATION: Katumanyane, A., Kanzi, A. M. & Malan, A. P. 2020. Sciarid pests (Diptera: Sciaridae) from undercover crop production in South Africa. South African Journal of Science, 116(3/4):#6822, doi:10.17159/sajs.2020/6822.
The original publication is available at https://www.sajs.co.za
The original publication is available at https://www.sajs.co.za
Keywords
Sciaridae, Roots (Botany) -- Diseases and pests -- South Africa, Diptera, Bradysia impatients, Fungus gnats, Root crops -- Diseases and pests -- South Africa
Citation
Katumanyane, A., Kanzi, A. M. & Malan, A. P. 2020. Sciarid pests (Diptera: Sciaridae) from undercover crop production in South Africa. South African Journal of Science, 116(3/4):#6822, doi:10.17159/sajs.2020/6822.