Fungicide resistance of Botrytis cinerea from strawberry to procymidone and zoxamide in Hubei, China

Phytopathology Research

Table 2 Fitness components, control efficacy and stability of Botrytis cinerea isolates from strawberry

Phenotype	Isolate	Resistance levels^a	Mycelium growth ^b	Osmotic sensitivity 8% (PIMG) ^c	Virulence (cm) ^d	Sporulation (× 10⁶/cm²)^e	Control efficacy ^f	Resistance stability EC50 (μg/mL)^g
Phenotype	Isolate	Resistance levels^a	Mycelium growth ^b	Osmotic sensitivity 8% (PIMG) ^c	Virulence (cm) ^d	Sporulation (× 10⁶/cm²)^e	Control efficacy ^f	1st	10th
Pro^S	S191	S	6.57	90.84	2.20	4.8	100	–	–
Pro^S	S377	S	6.57	97.85	2.23	4.0	100	–	–
Pro^S	S524	S	6.28	95.23	2.60	2.5	100	–	–
Pro^S	S572	S	6.26	95.21	2.45	2.1	100	–	–
	Mean		6.42A	94.78B	2.37A	3.36A	100A	–	–
Pro^R	S106	LR	5.61	104.66	2.62	6.2	23.37	1.52	2.176
Pro^R	S111	LR	5.98	101.61	2.39	3.2	11.56	2.45	2.799
Pro^R	WH36	LR	6.68	107.85	2.23	5.4	16.28	1.56	2.397
Pro^R	YD4	LR	4.59	110.49	2.35	3.2	24.36	1.64	3.338
	Mean		5.72A	106.15A	2.4A	4.52A	18.89B	1.79A	2.67A
Pro^R	S151	MR	6.46	102.29	2.33	4.3	12.52	3.48	4.511
Pro^R	S155	MR	6.68	103.02	2.54	6.3	21.05	4.05	5.999
Pro^R	S299	MR	6.26	106.78	2.40	2.2	23.13	3.86	2.779
Pro^R	YD3	MR	7.16	103.08	2.61	7.6	18.95	3.61	6.437
	Mean		6.64A	103.79A	2.47A	5.11A	18.91B	3.75A	4.93A
Zox^S	S104	S	7.12A	–	2.98A	3.83B	100A	–	–
Zox^R	S295	R	6.43	–	2.91	6.4	7.12	4.32	4.72
Zox^R	S329	R	6.74	–	2.01	7.2	20.29	4.53	4.41
Zox^R	S196	R	6.30	–	2.38	7.0	13.98	20.25	19.22
Zox^R	S133	R	7.08	–	3.54	6.8	11.01	4.83	4.59
Zox^R	S155	R	7.16	–	2.84	5.0	22.45	6.73	6.87
Zox^R	S298	R	7.33	–	2.1	5.4	18.22	5.95	6.11
	Mean		6.84A	–	2.64A	6.38A	15.51B	7.76A	7.65A

^a Resistance levels of procymidone resistant isolates. LR and MR represent low and moderate resistance, respectively; ^b Mycelium growth was measured as colony diameter (cm) at 60 h under 23 °C; ^c The percentage of inhibition of mycelial growth (PIMG) was calculated using the formula PIMG = [(C-N)/(C-5)] × 100, where C is the colony diameter of the non-treatment control, and N is that of the sodium chloride treatment; ^d Virulence was shown as the diameter of lesion size (cm) at 3 days under 23 °C; ^e Mean number (×10⁶) of conidia per square centimeter; ^f Control efficacy was expressed as the percentage of the mean diameter of the control minus the mean diameter of the treatment divided by the mean diameter of the control; ^g Stability of procymidone/zoxamide resistant isolates after 10 consecutive transfers on fungicide free medium (1^st and 10^th transfer), means were compared between 1^st and 10^th transfers of each group. Means indicate the sensitive and corresponding resistant groups, values within a column followed by the same letter are not significantly different according to LSD test (P = 0.05)