The Influence of Chitin- and Chitosan-Based Soil Amendments on Pathogen Severity of Apple and Pear Scab

Glynn C. Percival; Sean Graham; Christopher Percival; Jonathan Banks

doi:10.48044/jauf.2023.006

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Table 1.

Products, active ingredient, concentration, directions for use, and supplier of treatments^{^a} used.

Commercial name	Active ingredient	Concentration applied	Directions for use	Supplier
Topas	Penconazole	1.5 mL/L of water	See “Materials and Methods”	Syngenta UK Ltd, Fulbourn, Cambridgeshire, UK
Chitin	Chitin	120 g/m² under the canopy = 360 g per tree applied	Once as a top dressing in March or as buds swell	Tidal Vision, Bellingham, WA, USA
Chitosan	Chitosan	120 g/m² under the canopy = 360 g per tree applied	Once as a top dressing in March or as buds swell	Tidal Vision, Bellingham, WA, USA
Crab meal	Crab meal	0.75 kg under the canopy per tree applied	Once as a top dressing in March or as buds swell	Ocean Crest Seafoods Inc., Gloucester, MA, USA
Liquid chitosan	Chitosan	1.0 mL/5 L of water per m² under the canopy = 3 mL per tree applied	One weekly drench for the first three weeks, and then one drench per month throughout the growing season; start first drench in March or as buds swell	Viresco UK Ltd, Thirsk, North Yorkshire, UK
Agrinos 5-0-0	Chitin	0.8 g/L of water per m² under the canopy = 2.4 g per tree applied	Every 2 weeks throughout the growing season; start first drench in March or as buds swell	Hortifeeds, Park Farm, Kettlethorpe, Lincoln, UK
Control	Water	–	–	–

↵^aAll treatments based on manufacturers’ recommended efficacy rates.

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Table 2.

The influence of penconazole and chitin/chitosan-based soil amendments on pathogen severity of apple scab (Venturia inaequalis) on Malus sylvestris (crab apple) containerised seedlings^{^a}.

Treatment	Leaf scab severity^{^b}	SPAD	F_V/F_M	PI_ABS
Control (water)	3.8d	19.9c	0.700de	3.61d
Penconazole	1.0a	38.4g	0.813g	7.65h
Chitin (2.0%)	–	14.3ab	0.564b	1.47a
Chitin (1.5%)	–	15.9b	0.639c	2.75bc
Chitin (1.0%)	1.6b	34.9f	0.800fg	6.06f
Chitin (0.5%)	2.2c	31.3e	0.770f	4.97e
Chitin (0.25%)	3.6d	22.8d	0.728e	4.43e
Chitosan (2.0%)	–	13.5a	0.497a	1.34a
Chitosan (1.5%)	–	16.0b	0.550b	2.45b
Chitosan (1.0%)	1.5b	34.2f	0.803fg	6.82g
Chitosan (0.5%)	3.8d	19.4c	0.711de	3.17cd
Chitosan (0.25%)	3.7d	20.0c	0.690d	3.47d
Significance of Treatment (T)	< 0.001	< 0.001	< 0.001	< 0.001

↵^aNumbers within a column followed by a common letter are not significantly different according to Tukey’s Honest Significant Difference test (P = 0.05).
↵^bMean of 100 leaves from 10 trees (10 leaves per tree) placed in a completely randomised block design.

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Table 3.

The influence of penconazole and chitin/chitosan-based soil amendments on pathogen severity of pear scab (Venturia pirini) on Pyrus communis ‘Conference’ (pear ‘Conference’) under field conditions^{^a}.

Treatment	Leaf scab severity^{^b}	Fruit scab severity^{^c}	SPAD	F_V/F_M	PI_ABS	Fruit yield (kg)
Control (water)	3.5c	1.8b	36.4a	0.828a	7.47ab	8.44a
Penconazole	2.0a	1.0a	42.4b	0.834a	9.92c	10.80c
Chitin (1.0%)	2.1a	1.1a	44.1b	0.832a	9.96c	10.10abc
Chitosan (1.0%)	2.2a	1.0a	42.0b	0.832a	10.1c	10.56bc
Crab meal	3.0b	1.7b	41.9b	0.830a	7.65ab	8.92ab
Liquid chitosan	2.4a	1.3a	42.8b	0.834a	9.07bc	8.94ab
Agrinos 5-0-0	3.5c	1.9b	37.6a	0.832a	6.84a	9.24abc
Significance of Treatment (T)	< 0.001	< 0.001	< 0.001	< 0.445	< 0.001	< 0.001

^aNumbers within a column followed by a common letter are not significantly different according to Tukey’s Honest Significant Difference test (P = 0.05).
↵^bMean of 50 leaves from 5 trees (10 leaves per tree).
↵^cMean of 50 fruits from 5 trees (10 fruits per tree).