Efficacy of Bumble Bee Disseminated Biological Control Agents for Control of Botrytis Blossom Blight of Rabbiteye Blueberry

Figures & data

Table 1 Bumble Bee Dissemination of Fluorescent Dye at an Organic Blueberry Farm Located in Stone County, Mississippi, USA ^z

Sample date	Average number flowers/stem	Flowers fluorescing (%)
March 21	26.4	5.6
March 23	21.2	13.8
March 25	24.4	17.2
March 27	17.3	27.9
March 29	19.1	31.5
Average	21.7	19.2
^zTwo hives were placed in the field on 19 March 2008 at an average distance of 23 meters from each bush. Two additional hives were placed in the field on 25 March 2008. Fluorescent dye was put in the exit tube of each hive each day.

Table 2 Bumble Bee Dissemination of Fluorescent Dyes from Two Hives (One with Yellow or Pink Dye in Exit Hole; the Other with White Dye in Exit Hole) Located in a Research Blueberry Field at Poplarville, Mississippi, USA (March 2008)

	UV field count		March 21, # of clusters		March 23, # of clusters		March 25, # of clusters
Plant	# Open clusters	# Fluorescing	Collected	Fluorescing	Collected	Fluorescing	Collected	Fluorescing	Total, % fluorescing
1	339	52	33	8	19	14	20	15	51
2	91	0	10	0	23	2	19	0	4
3	173	1	15	0	27	2	18	1	5
4	226	2	26	0	36	3	17	2	6
5	173	1	20	1	29	2	21	7	14
6	152	36	20	0	24	3	18	9	19
7	117	51	14	8	25	6	21	14	47
8	102	16	13	1	27	7	20	4	20
9	172	9	20	0	24	5	21	2	11
10	52	2	11	0	13	2	20	2	9
Total	1,597	170	182	18	263	57	195	56
Average, %		11		10		22		29	19

Table 3 Observations of Bees Exiting and Returning to Hives Containing Fluorescent Dye in the Blueberry Field at Poplarville, Mississippi, USA on March 20 and March 23, 2008

March 20, 2008					March 23, 2008
	Observations		Number of bees			Observations		Number of bees
Hive with	Started	Ended	Exiting	Returning	Hive with	Started	Ended	Exiting	Returning
Yellow dye	16:25	16:30	8	2	Pink dye	12:20	12:30	0	2
	16:45	16:55	4	2		12:40	12:50	2	2
						16:08	16:18	0	0
						16:28	16:38	0	0
White dye	16:35	16:45	1	4	White dye	12:30	12:40	2	2
	16:55	17:05	5	6		12:50	13:00	1	4
Total	35 min		18	14		60 min		5	10

Table 4 Recovery of Gliocladium (Prestop) from Styles of ‘Tifblue’ Blueberry Flowers Collected from the Field 2, 5, 8, and 10 Days after First Release of Bumble Bees Carrying Prestop Fungicide ^y

Flower collection date	Days after 1st bee release	Number of clusters collected	Number of styles plated	Styles with Gliocladium (%)
March 21, 2008	2	19.33 ^z	103.83 ^z	5.64
March 24, 2008	5	19.50	108.50	10.30
March 27, 2008	8	22.67	121.17	31.74
March 29, 2008	10	28.67	143.67	12.28
^yStyles were placed on acid potato dextrose agar containing Triton, and the number of styles with Gliocladium colonies was counted 4–6 days after plating.
^zAverage number from six replications.

Table 5 Main Effects and Interactions of Corolla Color (Percentage) and Disease Score Six Days after Inoculation of Detached Blueberry Stems with Botrytis cinerea, and the Significance of Main Effects and Interactions on the Four Experimental Parameters for Treatments Involving Application by Bees of a Biocontrol Agent (Prestop) to Blueberry Flowers (Factor A) and Their Subsequent Inoculation with Botrytis (Factor B) as Determined by Factorial Analysis of Variance

Treatment	N	% Brown corollas		% Semi-brown corollas		% White corollas		Disease score ^z
Bagged (Factor A −)	120	23.2	a ^y	24.4	a	52.4	b	2.3	a
Prestop (Factor A +)	119	10.0	b	18.8	b	71.3	a	1.9	b
LSD		5.3		5.1		5.9		0.3
Inoculum
Botrytis (Factor B −)	143	26.3	a	30.9	a	42.8	b	2.7	a
Water (Factor B +)	96	2.3	b	7.7	b	90.1	a	1.4	b
LSD		5.4		5.2		6.0		0.3
Interactions
Bagged × Botrytis (−/+)	72	37.4	a	34.2	a	28.5	c	3.1	a
Prestop × Botrytis (+/+)	71	15.0	b	27.6	a	57.4	b	2.2	b
Bagged × Water (−/−)	48	1.9	c	9.8	b	88.3	a	1.2	c
Prestop × Water(+/−)	48	2.6	c	5.6	b	91.8	a	1.5	c
LSD		7.7		7.4		8.5
		% Brown corollas		% Semi-brown corollas		% White corollas		Disease score
Source of Variation	Treatments	F value	P > F	F value	P > F	F value	P > F	F value	P > F
Factor A	Prestop (+/−)	28.7	<.0001	23.4	<.0001	6.4	<.000	7.33	.007
Factor B	Botrytis (+/−)	51.6	<.0001	78.9	<.0001	86.9	<.000	73.0	.0001
A × B		18.6	<.0001	5.8	<.0001	1.4	0.24	13.5	.0003
^zDisease development was rated on a visual scale of 0 to 7, where 0 = no visible symptoms to 7 = lesion extends from dead cluster into stem.
^yMean values followed by different letters in the same column within a group are significantly different as determined by Fisher's protected least significant difference (LSD) at α = 0.05.