Posts Tagged: fungicides

Use of Soil Applied Fungicides for Reduction of Charcoal Rot caused by Macrophomina in Strawberry

Introduction: The difficulty of controlling Macrophomina, the causal agent in charcoal rot in strawberry, in California has brought about a renewed interest in non-conventional methods for its management.

The following study is an attempt to investigate two soil applied fungicides and their effectiveness in mitigating loss from Macrophomina infection.

Materials and Methods: The trial was done as a randomized complete block design of four replicates of one bed 35 foot long by 4 foot wide per treatment on Monterey variety strawberries in a field known to be infested with Macrophomina in Salinas, California. See the picture below for a demonstration of the disease severity of the disease on one side of the field; the side on which the study was done was unfortunately (for the study, not the grower) not nearly as severe.

Application: Applications of both fungicides were done 3 times in the early part of the year, March 2, April 12 and May 3, 2017. The fungicide Rhyme (which is labeled for soil application for management of charcoal rot), applied at 7 oz/acre and Merivon, applied at 11 oz/acre, were applied in approximately 40 gallons of water per treatment pumped in with a gasoline powered pump hooked up to the double rows of high flow drip tape. Injection consisted priming the irrigation tape, injecting the material and then flushing the lines.

It is important to note that the use pattern deployed here for Merivon is as of this time NOT a labeled application.

Evaluation:

Plant diameters were taken in the early part of the season to gauge any initial differences in plant vigor.   One measurement across the widest part of ten plants was taken in each treatment replicate and reported in cm.

Yield of strawberry fruit was the principle measure of plant performance in this trial. Fruit picking commenced in May with weekly picks, and then continued from June through early September with twice weekly picks. Only marketable fruit was included, and it was weighed and counted from each plot.

Since the work here involved two fungicides, one evaluation of powdery mildew was also done on May 9, 2017 but the amount of mildew was insufficient for a significant evaluation.

Results were tested statistically on ARM version 9 using a multiple comparison procedure (Least Significant Difference at the 95 percent level of significance) to determine whether the means of counts and percentages per treatment were significantly higher or lower from the other treatments.

Results and Discussion:

Results are given in Tables 1 and 2 below. While disease was evident with weakening plants from the beginning of May on, it was not as severe as the outbreak on the other side of the field and no plants were lost in any of the treatments.

Table 1: Plant Diameters on Two Dates (in cm) of Strawberry in Plots of Soil Applied Fungicides Rhyme and Merivon Compared to an Untreated Check¹

Treatment	Apr 12	May 3
Untreated	32.2 a	33.1 a
Rhyme	32.7 a	34.7 a
Merivon	32.7 a	35.7 a

 

Table 2: Fruit Yield and Size (in g) of Strawberry in Plots of Soil Applied Fungicides Rhyme and Merivon Compared to an Untreated Check¹

Treatment	May totl	May size	June totl	June size	July totl	July size
Untreated	2214a	35.6 a	4408a	28.4 a	5636a	21.0 a
Rhyme	2169a	35.3 a	4720a	28.1 a	5525a	21.9 a
Merivon	2216a	34.6 a	4454a	27.9 a	6064a	22.1 a

 

Treatment	Aug totl	Aug size	Sept total	Sept size	Season total	Size avg
Untreated	3051a	21.2b	849.0a	20.9 b	16157a	24.1 a
Rhyme	2617a	22.2a	784.5a	21.5 ab	15816a	24.8 a
Merivon	2752a	21.9a	1009a	22.3 a	16496a	24.6 a

1Method used to discriminate among means Fisher's least significant difference procedure. Treatments followed by the same letter have no statistically significant differences.

As seen in the tables above, use of the soil applied fungicides in this trial did not result in any significant yield differences between any of the treatments. It is interesting to note however, that average fruit size in the later months of the study, those being August and September, was significantly larger in the treated plots than the untreated.

Many thanks to the grower, BASF and FMC for really great support on getting this trial done.

The use of several pesticides is described in this post.  As always, before using any of these or other pesticides, consult the label and if there are further questions contact your local County Agricultural Commissioner.

Some of the Macrophomina action on the other side of the test field.

Fungicide Trials for Fruit and Foliar Pathogens of Strawberry 2013-2014

Summary: In 2014, the authors evaluated fungicide products against a slate of several registered fungicides and an untreated control. Fungicides were tested for efficacy against gray mold caused by Botrytis cinerea and powdery mildew caused by Podosphaera aphanis.

Introduction: The authors have been engaged in studying fruit and foliar pathogens in strawberry since 2007. While this group of pathogens includes anthracnose caused by species of Colletotrichum, leather rot caused by Phytophthora cactorum and angular leaf spot caused by Xanthomonas fragariae, the fungicide screening of 2014 concentrated on the two most common problems: gray mold caused by Botrytis cinerea, and powdery mildew caused by Podosphaera aphanis. Year after year these diseases are the most important foliar/fruit concerns for growers, and subsequently garner the most attention from fungicide distributors and manufacturers.

 

Materials and Methods:

Powdery Mildew: The trial consisted of treatments (Table 1) arranged in a randomized complete block design with each treatment replicated four times, on the Holly Ranch managed by Dole on the variety Monterey. Applications of all materials were made in the equivalent of 150 gallons per acre with a motorized backpack sprayer and hand held boom configured with ten 8001 flat fan nozzles operating at 120 psi, which is intended to closely mimic the conditions of commercial application. Applications of all materials were made two weeks apart: May 16, May 28, June 16, and June 24, 2014.

Powdery mildew evaluations were done on June 5, June 19 and July 7 and consisted of taking ten strawberry leaflets (per plot) of young to mid-age and assigning a percentage on a scale of 0-100% (in 10% increments) to the level of powdery mildew severity on the underside.

 

Table 1: 2014 Powdery Mildew Treatments

 

	Test Material	Rate/acre
	Thiram   24/7	2.6   qt
	Thiram   24/7 2.6 qt+ Procure 480 SC	8   fl oz
	Thiram   Granu-Flo	4.4   lb
	Pyriofenone	4   fl oz
	Pyriofenone	5   fl oz
	Pyriofenone 4 fl oz +   Quintec	6 fl oz
	Quintec	6   fl oz
	Rally	5   oz
	Rally   5 oz w/ Quintec	5   fl oz
	Merivon   + Nufilm P	8   fl oz + 0.01% v/v
	Merivon   + Nufilm P	10   fl oz + 0.01% v/v
	Pristine	23   oz
	Torino   3.4 fl oz w/ Mettle	5   fl oz
	Isofetamid	17   fl oz
	Isofetamid + IB8111	10.3 fl oz + 5.57 fl oz
	Isofetamid + 18121	10.3 fl oz + 16.5 fl oz
	Isofetamid + IB18220	10.3 fl oz + 7.6 fl oz
	Untreated   check	-

 

Results for 2014 Trial

 

Table 2: 2014 Powdery Mildew Evaluation- Percent Leaf Disease by Treatment

 

Character   Rated		% Infest		% Infest		% Infest
Rating   Date		Jun-5-2014		Jun-19-2014		Jul-7-2014
Number   of Decimals		2		2		2
Trt	Treatment
	Name	1		2		3
1	Thiram   24/7 2.6 qt	23.44	a	17.25	bcd	23.08	abc
2	Thiram   24/7 2.6 qt+ Procure 480 SC 8 fl oz	11.88	cde	7.25	gh	14.64	def
3	Thiram   Granu-Flo 4.4 lb	16.25	bc	18.00	bc	26.35	a
4	Pyriofenone   4 fl oz	13.44	cde	13.00	def	15.85	cde
5	Pyriofenone   5 fl oz	13.13	cde	8.25	fgh	8.90	fgh
6	Pyriofenone 4 fl oz + Quintec   6 fl oz	15.31	bcd	11.25	efg	13.60	d-g
7	Quintec   6 fl oz	15.00	bcd	15.50	b-e	23.55	ab
8	Rally   5 oz	16.25	bc	19.25	b	29.40	a
9	Rally   5 oz w/ Quintec 5 fl oz	10.31	c-f	14.00	cde	17.26	bcd
10	Merivon   8 fl oz + Nufilm P 0.01%	6.88	ef	4.25	h	6.76	hi
11	Merivon   10 fl oz + Nufilm P 0.01%	3.75	f	3.75	h	3.49	i
12	Pristine   23 oz	21.25	ab	13.00	def	22.66	abc
13	Torino   3.4 fl oz w/ Mettle 5 fl oz	7.19	ef	7.00	gh	8.67	gh
14	Isofetamid   17 fl oz	11.88	cde	8.75	gh	11.47	d-h
15	Isofetamid 10.3 fl oz +   IB8111 5.57 fl oz	10.63	cde	11.75	efg	15.71	cde
16	Isofetamid 10.3 fl oz + 18121   16.5 fl oz	11.94	cde	4.75	h	10.84	e-h
17	Isofetamid 10.3 fl oz +   IB18220 7.6 fl oz	9.06	def	7.25	gh	10.98	d-h
18	Untreated   check	20.94	ab	24.75	a	30.04	a
LSD   (P=0.05)		6.768		4.920		0.838t
Standard   Deviation		4.786		3.479		0.593t
CV		36.12		29.53		14.89

Means followed by same letter do not significantly differ (P=0.05, LSD)

 

Botrytis Gray Mold: The trial consisted of treatments (Table 3) arranged in a randomized complete block design with each treatment replicated four times, on the Holly Ranch managed by Dole on the variety Monterey. Applications of all materials were made in the equivalent of 150 gallons per acre with a motorized backpack sprayer and hand held boom configured with ten 8001 flat fan nozzles operating at 120 psi, which is intended to closely mimic the conditions of commercial application. Applications of all materials were made two weeks apart May 16, May 28, June 16, and June 24, 2014.

 

Evaluations for Botrytis infected fruit were made during the weekly fruit harvest by a professional crew of research plot harvesters beginning May 21 and continuing until July 16. Culls were sorted and examined for symptoms and signs of gray mold disease, and a percentage of gray mold infected fruit was calculated from the total fruit harvested from that plot.  Data results (Table 4) is presented as a percentage of Botrytis infected fruit from the  total amount harvested.

 

Table 3: Test materials for Botrytis study

 

	Test Material	Rate/acre
	Thiram   24/7	2.6   qt
	Thiram   24/7 2.6 qt+ Procure 480 SC	8   fl oz
	Thiram   Granu-Flo	4.4   lb
	Merivon   + Nufilm P	8   fl oz + 0.01% v/v
	Merivon   + Nufilm P	10   fl oz + 0.01% v/v
	Pristine	23   oz
	Isofetamid	17   fl oz
	Isofetamid + IB8111	10.3 fl oz + 5.57 fl oz
	Isofetamid + 18121	10.3 fl oz + 16.5 fl oz
	Isofetamid + IB18220	10.3 fl oz + 7.6 fl oz
	Untreated   check	-

 

Table 4: Results for 2014 trial

 

Character   Rated		% Bot		% Bot		% Bot		%Bot		%Bot
Rating   Date		Jun-4-2014		Jun-11-2014		Jun-18-2014		Jun-25-2014		Jul-3-2014
	Treatment   Name	3		4		5		6		7
1	Thiram   24/7 2.6 qt	4.21	a	1.68	a	3.15	ab	8.75	a	18.01	a
2	Thiram   Granuflo 4.4 lbs	7.22	a	1.07	a	1.95	abc	15.17	a	18.39	a
3	Thiram   24/7 + Procure 480 SC	9.27	a	2.49	a	1.64	abc	14.36	a	16.198	a
4	Merivon   @ 8 fl oz	5.52	a	1.49	a	0.74	c	15.56	a	16.268	a
5	Merivon   @ 10 fl oz	5.96	a	1.25	a	0.69	c	15.73	a	17.233	a
6	Pristine   @ 23 oz	7.46	a	1.44	a	3.49	a	12.32	a	14.708	a
7	Isofetamid   @ 17 fl oz	6.54	a	1.07	a	1.67	abc	12.70	a	17.975	a
8	Isofetamid @ 10.3 fl oz +   IB8111 @ 5.57 fl oz	5.67	a	1.58	a	1.35	bc	10.86	a	20.643	a
9	Isofetamid @ 10.3 fl oz + IB18121 @ 16.5 fl oz	4.69	a	2.11	a	2.63	ab	8.60	a	12.815	a
10	Isofetamid @ 10.3 fl oz +   IB18220 7.6 fl oz	5.59	a	1.85	a	1.87	abc	9.22	a	19.803	a
11	UTC	13.52	a	1.68	a	3.14	ab	7.66	a	14.720	a
LSD   P=0.05		0.344t		0.276t		0.265t		0.282t		8.9782
Standard   Deviation		0.238t		0.191t		0.183t		0.196t		6.2180
CV		27.11t		46.46t		39.85t		17.79t		36.62

 Means followed by same letter do not significantly differ (P=0.05, LSD)

Discussion of Results for 2014 Trial:

 

Powdery Mildew: Control of powdery mildew by both rates of Merivon and a rotation of Torino and Mettle was exceptional, with percentages of infection significantly lower than many treatments in each of the three evaluation dates.

 

Looking at the last rating date on July 7, neither formulation of Thiram controlled powdery mildew, but the inclusion of Procure together with Thiram 24/7 did result in disease percentages below the untreated control. Test compounds isofetamid and pyriofenone had lower percentages of mildew than the untreated control. Rally 40W did not have significantly lower percentages of mildew than the untreated control.

 

Botrytis: With the exception of the June 18 evaluation date, no significant differences were found between any of treatments. On June 18, both treatments of Merivon demonstrated lower levels of Botrytis infected fruit than the untreated control, Thiram 24/7, isofetamid @10.3 fl oz + IB8111 and Pristine.

 

Final Note: The use of fungicides, including unregistered materials, is the topic of this article. Before using any of these products, check with your local Agricultural Commissioner's Office and consult product labels for current status of product registration, restrictions, and use information.

 

Acknowledgments.

We thank Patty Ayala, Kat Kammeijer and Monise Sheehan for their assistance with this trial. We acknowledge the California Strawberry Commission and cooperating companies, in particular Dole, for supporting this work.

 

Year One of a Test of Biological Fungicides in Strawberries.

This is simply a summary of one year of biological fungicide work in strawberries in 2012-2013 and should not be understood as a recommendation to use any of these products.  This investigation is will continue into 2013-2014 and will serve to confirm and adjust the work here.

Introduction: A number of biological fungicides registered for use in strawberries have not been thoroughly tested through empirical studies to give guidance to growers on their efficacy and use.

 

Materials and Methods:

Table 1 below is an outline of materials tested in 2012-2013.

The field involved in the study was organically farmed and had a tested infestation of Verticillium at the average level of 25 microsclerotia per treatment replicate.  Grower standard was managed as per grower practice, that is to say normal irrigation, fertility and pest management practices were applied.  This grower standard did not include any sort of biological fungicide either by dip or injection through the drip tape during the season.

Plot was replicated three times and each replicate consisted of at one bed of 180 feet in length. 

Application of the materials took place as indicated in the table below:

 

Table 1. List of treatments.

Test   Material	Application/   Use
Dazitol	6.25 gal/A   applied 3-5 days prior to planting
Biotam +   Serenade Soil	5 lbs/A   pre-plant application 3-5 days prior to planting followed by Serenade Soil @   4 qt/A (10 days after planting, and then Serenade Soil @ 2 qt /A applied   monthly after planting.  Second   application of Biotam 5 lbs/A and Serenade Soil @ 4 qt/A in February.
Serenade   Soil	Serenade   Soil @ 4 qt/A (10 days after planting, and then Serenade Soil @ 2 qt /A   applied monthly after planting.
Serenade   Soil	Serenade   Soil @ 4 qt/A (10 days after planting, and then Serenade Soil @ 4 qt /A   applied every 60 days after planting.
Actinovate   Rate 1	(1) 3 oz   per 100 gal root dip at planting. (2)   followed by 6 oz/A pre-plant in drip tape (3)   followed by 3 oz/A every 30 days in drip tape
Actinovate   Rate 2	(1) 3 oz   per 100 gal root dip at planting. (2)   followed by 6 oz/A pre-plant in drip tape (3)   followed by 6 oz/A every 30 days in drip tape
SoilGuard	Apply at   planting as root dip or planting furrow drench at 5 lb/ A and again through   drip tape every 4-6 weeks through harvest.
Double   Nickel 55	Apply at   planting at 1 qt /A (1/2 lb/A powder) as root dip or planting furrow drench   and again through drip tape every 4-6 weeks through harvest.
Terra   Clean 5.0	(1) 128 fl   oz/100 gal drench (2) 2   gal/A drip applied at planting (3) 1   gal/A drip applied 10 days post plant and 28 days post plant (4) 1   gal/A drip applied 60, 90 and 120  days   post plant
Terra Clean 5.0 + Serenade Soil	(1) 128 fl   oz Terra Clean /100 gal drench + Serenade Soil @ 6 qt/ A soil drench (2) 2   gal/A Terra Clean drip applied at planting followed by SS @ 3 qt /A (3) 1   gal/A Terra Clean + 3 qt /A Serenade Soil drip applied 10 days post plant and   28 days post plant (4) 1   gal/A Terra Clean + Serenade Soil @ 3 qt/ A drip applied 60, 90 and 120 days   post plant
Tainio	(1)   Spectrum @ 50 g / A + Pepzyme C @ 12.5 oz/A 2- 3 days preplant (2)   Biogenesis @ 1 lb/A+ Pepzyme C @ 12.5 oz/A as plant dip (3)   Pepzyme C monthly through drip tape (4) Micro   5000 @ 2.66 oz/A at 2 leaf stage foliar

Plant dips were made by suspending the requested rate of fungicide in approximately twenty gallons of water and submerging and soaking about a half a box of strawberry transplants (about 500 plants) thoroughly and then distributing to planting crews for transplant.  Note that in the case of the two Actinovate treatments, plants were held for one night to prior to transplant, ostensibly to establish the organism on the plant roots.

Drip applications were made with a portable pump injecting each fungicide.  Each application normally was preceded by filling the drip tape with clear water, injecting the mix and then further pumping in clear water to make sure the fungicide had moved well out of the drip tape.

 

Application dates:

Preplant application – 11/3/2012

            Dazitol

            Terra Clean 5.0

            Terraclean 5.0 + Serenade Soil

            Tainio Spectrum + Pepzyme C

            Biotam

 

Root dip + one overnight hold – 11/7/2012 (planted November 8)

            Actinovate rate 1

            Actinovate rate 2

Root dip and immediate planting – 11/8/2012

            Double Nickel 55

            Soilguard

            Biogenesis + Pepzyme C

 

10 days post – plant – 11/20/2012

            Serenade 4 qt

            Serenade 2 qt

 

Monthly applications (12/11/2012, 1/16/2013, 2/26/2013, 3/27/2013, 4/30/2013,  and 6/13/2013)

 

Terra Clean 5.0

Terraclean 5.0 + Serenade Soil

Tainio Spectrum + Pepzyme C

Serenade 4 qt

Serendade 2 qt

Actinovate rate 1

Actinovate rate 2

Double Nickel 55

Biotam applied 2/26/2013; Serenade 4 qt per acre applied other dates in treatment

Soilguard

 

Several dying plants from different areas of the test plots were sampled in July to confirm that Verticillium was the cause of plant death.

As a gauge of plant vigor from each treatment, strawberry plant diameters were measured February 13, and April 13.  Measurements were in centimeters and from twenty plants in each plot.

With the beginning of fruit ripening, fruit harvest was done weekly in each treatment replicate.   On each pick date, fruit from each plot was weighed and counted.

 

Results:

 

	Plant D cm 2/13/2013	Plant D cm 4/13/2013	Yield to 5/14/2013	April Total   Yield g/plot
Actinovate   r1	14.05a	16.25a	3894.00a	2175.00ab
Actinovate   r2	13.70ab	16.42a	3818.33a	2428.00a
Biotam	11.47b	15.77a	2176.67b	1377.00b
Dazitol	11.70b	17.70a	2505.67ab	1568.00ab
Double   Nickel 55	12.65ab	15.92a	3084.00ab	1637.00ab
Serenade   4 qt +2 qt	11.57b	16.65a	2853.00ab	1471.67b
Serenade   4 qt +4 qt	12.42ab	16.02a	2621.00ab	1459.67b
Soilguard	11.85b	16.78a	2993.33ab	1652.33ab
Tainio	12.93ab	16.95a	3454.00ab	2075.33ab
Terraclean	11.50b	16.78a	2284.00b	1406.67b
Terraclean   + Serenade	12.47ab	17.11a	2656.33ab	1559.67ab
Untreated   grower standard	11.70b	17.90a	2145.00b	1189.00b

Means followed by same letter do not significantly differ (P=.05, Student-Newman-Keuls)

 

	May Total   Yield g/plot	June Total   Yield g/plot	July Total   Yield g/plot	Aug Total   Yield g/plot	Total Yield g/plot
Actinovate   r1	3741.67a	2791.00a	1902.33a	140.64a	16820.67a
Actinovate   r2	3069.67a	3237.67a	2812.33a	149.35a	17201.34a
Biotam	2254.00a	3251.33a	3402.00a	503.14a	14468.33a
Dazitol	2514.67a	3075.33a	3049.33a	269.16a	14625.00a
Double   Nickel 55	3038.67a	2837.67a	2573.67a	203.64a	15052.67a
Serenade   4 qt +2 qt	3244.67a	3287.00a	3623.67a	371.49a	16887.67a
Serenade   4 qt +4 qt	2959.67a	3617.67a	3236.33a	362.02a	16157.00a
Soilguard	3212.33a	3331.67a	2887.00a	359.45a	16352.33a
Tainio	3409.00a	3687.33a	3190.33a	170.27a	18145.00a
Terraclean	2496.67a	2997.00a	2750.00a	125.01a	13681.33a
Terraclean   + Serenade	2544.00a	2810.00a	2230.00a	191.78a	13454.33a
Untreated   grower standard	2812.00a	4019.33a	3800.00a	306.15a	16150.33a

Means followed by same letter do not significantly differ (P=.05, Student-Newman-Keuls)

 

Plant diameters measured on February 13, 2013, were significantly larger in the low rate of Actinovate than the other treatments with the exception of the high rate of Actinovate, Tainio and Double Nickel 55.

Both rates of Actinovate realized higher fruit yield than all other treatments except for the Dazitol, in cumulative fruit yield, which included six weekly harvests, up to May 14, 2013.  No further differences were realized between May and August.

As noted above, this field has a very high infestation of Verticillium and all plots began to experience pronounced plant dieback in June, with some 60-80% remaining alive or declining and by end of July, nearly all plants in all replicate plots had died.   There was a trend for plants which had produced larger amounts of fruit in April and May to experience lesser fruit production lesser vigor and earlier dieback as the season progressed.

 

Conclusion

The results of this trial are encouraging.  In the early part of the season up through the middle of May, several treatments had significantly higher amounts of fruits harvested than the grower standard.  Nonetheless, none of the treatments provided sufficient protection to the plants to prevent an almost complete die out of the plants by August, effectively ending the season.

 

 

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