European Journal of Plant Pathology (2020) 157, 433-439

Evair Cintra Julião, Marthony Dornelas Santana, Rejane do Livramento Freitas-Lopes, Alberto dos Passos Vieira, Josabete Salgueiro Bezerra de Carvalho and Ueder Pedro Lopes (2020)
Reduction of brown leaf spot and changes in the chlorophyll a content induced by fungicides in cassava plants
European Journal of Plant Pathology 157 (2), 433-439
Abstract: Brown leaf spot (BLS), caused by the fungus Clarohilum henningsii, is one of the most common leaf diseases in cassava, leading to losses in root yield due to the extensive defoliation of the plants. Despite this, BLS has been neglected and little is known about the disease. This study aimed to evaluate the ability of systemic fungicides (cyproconazole, thiophanate-methyl, pyraclostrobin, tebuconazole, azoxystrobin, and flutriafol) to inhibit the in vitro growth of C. henningsii isolates and to control BLS in cassava plants. In addition, we verified the effect of the fungicides on the plant physiology by measuring the chlorophyll a content. The results showed that the isolates were sensitive to all fungicides, as demonstrated by the low EC₅₀ (effective concentration of fungicide able to inhibit mycelial growth by 50%) values, which ranged from 0.06 to 0.43 μg.mL^-1. In addition, all fungicides were able to reduce the severity of BLS in cassava plants, but with different effectiveness. In general, flutriafol had the highest efficiency in reducing the disease severity under greenhouse and field conditions. Cassava plants treated with pyraclostrobin, azoxystrobin, and flutriafol had the highest increase of chlorophyll a content, which has not been reported in this crop. Based on our results, flutriafol is the most promising fungicide to control BLS in cassava, since it had the highest effectiveness in reducing the disease and provided the highest increase in the chlorophyll a content of the plants.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Ueder Pedro Lopes

Research topic(s) for pests/diseases/weeds:
control - general

---

Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Clarohilum henningsii	Cassava (Manihot esculenta)	Brazil (NE)