Status Update on Organic Blueberries in Michigan

Figures & data

TABLE 1 Effect of 2008 and 2009 Fertilizer Applications on 2009 Leaf Nutrient Levels at the MSU Organic Blueberry Planting

	%					PPM
	N	P	K	CA	MG	ZN	MN	FE	CU	B
Compost	1.84	0.11	0.81	0.28	0.13	9	86	42	1.1	23
Conventional	1.48*	0.09	0.65	0.34	0.17	10	58	37	1.0	16
McGeary	1.53*	0.09	0.64	0.34	0.17	10	67	37	1.1	16
*Denotes deficient levels of nitrogen.

TABLE 2 Labor Costs Associated with Hand Weeding on Nine Different Groundcover Treatments at the MSU Organic Blueberry Planting in 2008 (Assumes Pay Rate of $10/hr)

Ground cover/mulch	Weeding time (hr/hectare)	Labor cost ($/hectare)
No mulch	291	2,915
Perforated plastic mulch—white	131	1,309
Woven weed barrier—black	183	1,828
Wood/bark chips	111	1,112
Fresh wood chips	104	1,037
Pine bark nuggets	151	1,507
Wheat straw	57	568
Spoiled grass hay	69	692
Burlap sacks	114	1,136

FIGURE 1 Average (+SEM) colony forming units collected from plots fertilized with McGeary's organic fertilizer, compost, or conventional fertililzers for: (a) bacillus and (b) fungi from soil collected at the MSU organic blueberry planting. Bars within a year with different numbers differed significantly (p = 0.05).

TABLE 3 Analysis of Variance Significance and Interactions of Cover Crop and Fertilizer Effects on Beneficial and Total Cultivable Bacteria and Fungi in an Organic Blueberry Trial, East Lansing, MI, 2008–2009

	Probability (H 0 = 0)
Effect	Num df	Den df	Fungi	Trichoderma	Streptomycetes	Bacteria	Pseudomonas	Bacillus	Soil pH
Cover crop	2	6	ns	ns	ns	0.01	ns	ns	ns
Fertilizer	2	18	<0.0001	ns	<0.001	ns	0.02	ns	ns
Year	4	18	ns	— ^z	<0.01	0.06	<0.01	ns	<0.0001 ^y
Cover crop * fertilizer	1	9	ns	ns	<0.0001	0.001	0.02	ns	0.02 ^y
Cover crop * year	2	9	<0.001	—	0.03	ns	ns	ns	0.0001 ^y
Fertilizer * year	2	9	0.02	—	<0.001	ns	0.02	ns	0.02 ^y
Cover crop * fertilizer * year	4	9	ns	—	0.005	ns	ns	ns	0.0086 ^y
Soil pH	1	9	ns	ns	<.0001	ns	<0.05	0.03
Soil pH * cover crop	2	9	ns	ns	ns	ns	ns	ns
Soil pH * fertilizer	2	9	<0.01	ns	0.0001	0.01	ns	ns
Soil pH * Year	4	9	ns	—	<0.01	ns	0.03	ns
Soil pH * cover crop * fertilizer	1	9	ns	ns	0.0001	ns	ns	ns
Soil pH * cover crop * year	2	9	<0.001	—	<0.04	<0.01	0.05	ns
Soil pH * fertilizer * year	2	9	0.02	—	<0.001	ns	0.02	ns
Soil pH * cover crop * fertilizer * year	4	9	ns	—	<0.01	0.45	ns	ns
^zNo data, only measured in 2009.
^yDenominator df = 27.

FIGURE 2 Average (+SEM) insect damage from leafminers and Japanese beetles on plants fertilized with McGeary's organic fertilizer, compost, or conventional fertilizers at the MSU organic blueberry planting. There was no significant difference among treatments in the level of pest infestation.

TABLE 4 Japanese Beetle Feeding Damage to Blueberry Foliage in Laboratory Bioassays

Treatment	Rate	1 DAT	4 DAT
Untreated	NA	6.25 ± 3.61 a	3.75 ± 2.14 a
Aza-Direct	16 oz/acre	3.13 ± 1.88 a	0.75 ± 0.75 bc
Aza-Direct	32 oz/acre	0.75 ± 0.25 a	0 ± 0 c
Pyganic	32 oz/acre	2.25 ± 0.96 a	2.5 ± 0.96 ab
Pyganic	64 oz/acre	2.25 ± 0.29 a	0.5 ± 0.29 bc
Surround	25 lb/acre	0.5 ± 0.29 a	3.25 ± 2.25 ab
Foliage was collected from plants at the MSU organic blueberry planting. Percentages are presented as ±SE and percentages with the same letters within a column are not significantly different at α = 0.05.