The Impact of Mineral Particle Film on Blackberry Diseases and Insects, and Primocane Fruit Quality and Yield

Blackberries are an important fruit crop in Arkansas. Although the majority of varieties that are grown are traditional floricane-fruiting varieties, there is an interest in using primocane-fruiting types to provide berries at a time of year (late summer, early fall) when market prices are at a peak. Unfortunately, there is little information available on managing diseases and insect pests on plants that are fruiting at this time of year. In addition, high late summer temperatures can have a negative impact on primocane-produced fruit production and quality. The use of mineral particle films such as kaolin clay (Surround WP^®) to lower leaf temperatures and protect plants from solar injury has been suggested as a way to enhance primocane fruit production. Experiments will be established on two commercial farms in northern and central Arkansas, (Sta-N-Step Farm near Fayetteville, AR, and Gillam Farms of Arkansas, near Judsonia, AR, respectively) and in eastern Texas to evaluate the effects of mineral particle film applications during the late season on blackberry production and on arthropod pests and diseases.

We have had a successful first year in our project.

Gillam Farms already had 2 year old established Prime Ark 45 primocane fruiting blackberries in production. However, Sta-N-Step planted 100 Prime Ark Traveler blackberries on April 22 and Moss Springs Farm planted 100 Prime Ark traveler plants on May 6, 2016. Drip irrigation was installed and landscape fabric was established on both sides of the row to help with soil moisture and weed management. Plants were allowed to grow during the summer (Fig. 3). A trellis system was installed in the fall on each row (Fig. 4). Plants were pruned as needed in January, 2017 to retain 5-6 healthy floricanes to ensure good development of the fall (2017) and 2018 primocane crop. A delayed dormant application of Sulforix (2% solution) was applied to both IPM treatments (IPM with and without Surround) in February. The plots will be fertilized according to soil test recommendations in April, 2017.

Project objectives:

Project objectives

To demonstrate the importance of primocane-fruiting blackberries in commercial horticulture operations as a way to extend harvest in the fall when market prices are at peak.
To demonstrate that high late summer temperatures in the southeastern states can be managed with mineral particle films (kaolinite) sprays.
To determine if mineral particle film sprays can provide protection from various insects and diseases.

Cooperators

Sherri Sanders (PI), White County Extension Agent, Searcy, AR, involved in overall project coordination, visited participating farmers, and attended area, state, and national meetings to disseminate information; Sherri supervised: Lewis Western, farm labor, and Misty Watkins, trap runner
Donn T. Johnson (Co-PI), Professor of Department of Entomology, University of Arkansas-Fayetteville, AR, coordinated weather monitoring, pest monitoring and pest management decision-making at all three participating grower plantings. This included placement and downloading of temperature logger data by treatment; sampling to estimate densities of insects and mites by treatment; applying Surround to whitewash plants and help growers decide need and to apply insecticide or fungicide applications by treatment plot; to coordinate and assist with harvest and summarize yields by treatment; and input data, conduct data analyses of temperatures, rainfall, pest densities, and damage by treatment; Donn supervised:
- Barbara Lewis (Program Associate), Jessica LeFors (Masters graduate student), Lizabeth Herrera (Masters graduate student), Rosalee Knipps (Masters graduate student), Anna Mays (hourly), Katherine Massiel Del Cid Palma (hourly), Carmen Bugher (Service Assistant I), Laura Teague (Service Assistant I)
John Clark, Distinguished Professor of Horticulture, University of Arkansas-Fayetteville, AR, was interviewed on video where he described the history of developing primocane-fruiting blackberry cultivars, recommended production practices and future research needs.
Craig Rothrock (Co-PI), Professor of Plant Pathology, University of Arkansas-Fayetteville, AR, evaluated blackberry disease in three participating blackberry plantings until he retired in August 2017.
Terry Kirkpatrick (Co-PI), Professor of Plant Pathology/Extension Plant Pathologist, University of Arkansas, Hope, AR, directed general plot oversight at Moss Berry Farms and took over assessing level of blackberry diseases by treatment in all three farms; Terry supervised:
- John David Barham (Program Associate), Tammy Hickey (Service Assistant II)
Jennie Popp (Co-PI), Professor of Agricultural Economics and Agribusiness and Area Director, Division of Agriculture Center for Agricultural and Rural Sustainability, University of Arkansas-Fayetteville, AR, directed revision of existing interactive sustainable blackberry budget to include all management practices used on these participating farms, analyzed all data and developed enterprise production budgets for each of the three farms; Jennie supervised:
- Leah A. English (Research Program Associate)
Karen Ballard (Evaluation), Professor of Program and Staff Development of Cooperative Extension, University of Arkansas-Little Rock, AR, Coordinated communications strategy to include project branding for all communications products, project team training, and producer of Virtual Field Trip; Coordination of overall project evaluation including team training related to data collection and reporting protocols, monthly management of analytics, oversight and evaluation of reach and effectiveness of outreach methods, bi-monthly facilitation of project process improvement communications to inform and improve project management and outreach; she supervised:
- Amanda McWhirt <amcwhirt@uaex.edu>
- Jackie Lee <jalee@uaex.edu>
- Leah Wasson <lwasson@uaex.edu> (Technical Assistant I in Office of Information Technology)
- Mary Poling <mpoling@uaex.edu>
- Kerry Rodtnick <krodtnick@uaex.edu>
- Julie Robinson <jrobinson@uaex.edu>
- Ricky Blair <rblair@uaex.edu>
- Nick Kordsmeier <nkordsme@uark.edu>
- Mary Hightower <mhightower@uaex.edu>
- Sam Boyster <sboyster@uaex.edu>
- Vonda Nutt <vnutt@uaex.edu>

Research:

Materials and methods: process involved in conducting the project and the logic behind the choices you made.

Objective 1. To demonstrate the importance of primocane-fruiting blackberries in commercial horticulture operations as a way to extend harvest in the fall when market prices are at peak.

Methods: Three farms (Gillam near Searcy, AR, Sta-N-Step near Tontitown, AR and Moss Springs in New Boston, TX) will plant and/or manage primocane-fruiting blackberry plants spaced 0.7 m apart. Plot set up, treatment application and data collection will be supervised by Sanders at Gillam Farm (Searcy, AR), Kirkpatrick at Moss Springs (New Boston, TX), and Johnson at Sta-N-Step (near Tontitown, AR).

At each planting, treatments were a randomized complete block design (four replications). These plants were trickle irrigated as needed. Treatment plots (listed under objective 2) each consisted of five to six individual plants arranged in a randomized complete block design (four replicates). In 2016 near Searcy, AR, a seven-year-old Prime-Ark® 45 primocane-fruiting blackberry planting had four, 30 m (100 ft) rows (blocks) set aside for this study. On 22 April 2016 near Tontitown, AR, 100 Prime-Ark® Traveler primocane-fruiting blackberry plants were planted in a 91 m (300 ft) long row and divided into four blocks. In April 2016 in New Boston, TX, 100 Prime-Ark® Traveler primocane-fruiting blackberry plants were planted in each of four 23 m (75 ft) long rows. After one year of growth in 2017, fruit were harvested by treatment plot twice weekly first from floricanes and later from primocanes at Tontitown and New Boston.

Application dates for Surround mineral particle film (kaolin clay) are listed in Table 1. These applications were made to whitewash the canopy in hopes of lowering the canopy temperature which may affect yield and prevent damage by insects such as spotted wing drosophila and Japanese beetles. Surround was also applied to whitewash emerging green terminals to prevent broad mite outbreaks. Only rains exceeding 0.25” rinsed Surround whitewash off blackberry canopy requiring re-application to maintain whitewash appearance (Table 2). In 2018, the New Boston, TX planting was not whitewashed with Surround because the grower did not want to commit extra labor to washing off the white residue from harvested berries. In 2018, Surround was applied to plants up to July 23 in Searcy, AR and up to June 18 (first green berry) near Tontitown, AR to minimize white residue on harvested fruit.

In 2018, plantings near Tontitown and New Boston had all floricanes pruned off at ground by bud break, removed from planting and fruit on primocanes harvested twice weekly. The grower at New Boston tipped vines in April, and pruned and tied canes to trellis on 22 May, 19 June and 22 Aug. From 18 June until early-July near Tontitown, the grower tipped emerging primocanes at height of 0.6 to 0.9 m (2 to 3 ft), tipped laterals at 0.5 m (1.5 ft) length and thinned each plant to 7 to 10 strong primocanes. The planting at Searcy was not harvested due to on-going sale of the property.

Table 1. Dates of applications of Surround mineral particle film to whitewash blackberry plants in Arkansas and Texas.

Searcy, AR		Tontitown, AR		New Boston, TX
2017	2018	2017	2018^a	2017	2018
May 31	May 25		May 10, 17, 24		None
June 17, 22, 27	June 11, 25	June 8, 18, 27	June 1, 18		applied
July 8, 14, 25	July 10, 23	July 1, 22 Aug. 3, 10, 17		July 17, 31 Aug. 8, 15

^a Surround applied up to first green berry on primocanes in late-June to prevent white residue on harvested berries.

Table 2. Rain gauge records of rainfall for Tontitown, AR where a rain exceeding 0.25” would rinse off the Surround mineral particle film whitewash from the blackberry canopy and require re-application.

	Rain (inches)
Date	2017	2018
21 May		0.9
16 June		0.25
18 June	1.8	1.3”
30 June	0.8
8 July	0.5
16 July		0.6
17 July		0.9
18 July		0.4
21 July		0.7
7 Aug.		0.5
12 Aug.	1.26
12-13 Aug.		0.83
13 Aug.	0.43
14-15 Aug.	0.39	0.95
15-16 Aug.	1.7
17 Aug.		1.5
19 Aug.		0.3
30 Aug.		0.6
7 Sep.		0.5
20 Sep		1.5

Results:

On 19 January 2017, the Tontitown grower was videotaped as he demonstrated winter pruning these 9-month old blackberry plants to retain four or five of the strongest floricanes (Link: https://www.uaex.edu/farm-ranch/crops-commercial-horticulture/sare-blog/sta-n-step-farm.aspx ). On 15 Aug. 2018, the project team produced a 59 min. Virtual Field Trip titled, Fall Producing Blackberry Production System (Link: https://www.youtube.com/watch?v=TZnuW-KA5CQ&t=260s) at the Sta-N-Step Berry Farm near Tontitown, AR.

In 2017 at New Boston, TX, the blackberry harvest totaled 96.7 lbs of berries from floricanes from 15 May to 12 June and 20.6 lbs of berries from primocanes from 29 July to 9 August (Table 3). In comparison, near Tontitown, AR, blackberry harvest totaled 13.5 lbs of berries from floricanes from 15 May to 12 June and 5.4 lbs of berries from primocanes from 29 July to 14 September (Table 4). There were significant differences in mean yields with the Surround only treatment being less than the Surround + Insecticide treatment on four dates at New Boston, TX (Table 2). The two dates with differences in Tontitwon, AR had the Surround plots yielding more berries than the insecticide treated plots (Table 4). Not sure why there were discrepancies between sites.

In 2018, the floricanes had been removed before bud break so harvest was from primocanes only. A total of 14 lbs and 11.7 lbs of berries, respectively, were harvested from the five plant plots of 2-yr-old Prime-Ark® Traveler blackberries at New Boston, TX (from 5 to 30 July) (Table 5) and Tontitown, AR (15 June to 14 September) (Table 6). Mean season total harvest weights per five-plant plot ranged from 2.5 lbs in untreated plots to 3.5 lbs. in plots whitewashed with Surround in May and June prior to green fruit development. There were no significant (P>0.05) differences in treatment mean yields in either location. This may be attributed to the fact that no Surround was applied to whitewash plants at the New Boston farm and the planting near Tontitown had five Surround applications from 10 May to 18 June when sprays ended at first green berry compared to applications in July and August 2017 (Table 1). This earlier whitewash cutoff date was to minimize white residue on harvested berries.

Table 3. Biweekly and season mean total harvest yields in lbs (±SE) per treatment plot of five Prime-Ark® Traveler blackberry plants during two cane production periods (F = floricane = earlier; P = primocane = later) in each of four treatment plots (n=4): Surround whitewash; Surround whitewash + insecticide; insecticide; or untreated plants. The F and P values were derived from log₁₀(x+0.1) transformed data from New Boston, TX (2017).

		Berry yield (lbs)
Date	Cane type	Sur	Sur + Cide	Cide	Untrt	Row total	F_3,3	P>F
15-May	F	0.2±0.02	0.2±0.05	0.2±0.02	0.2±0.04	0.7	0.82	0.5
17-May	F	0.4±0.03	0.6±0.09	0.5±0.05	0.5±0.08	2.1	1.9	0.2
19-May	F	0.8±0.11b	1.2±0.07a	0.8±0.02ab	0.8±0.09b	3.6	4.16	0.04*
20-May	F	0.5±0.06b	0.7±0.03a	0.6±0.02ab	0.7±0.08ab	2.5	4.82	0.03*
22-May	F	1.2±0.07b	1.7±0.1a	1.2±0.07b	1.5±0.06ab	5.6	7.27	0.009**
23-May	F	0.8±0.13	1.1±0.09	0.8±0.04	1.0±0.08	3.7	1.93	0.2
26-May	F	1.9±0.25	2.5±0.12	2.3±0.22	2.1±0.29	8.8	1.66	0.24
28-May	F	2.8±0.14	2.9±0.14	3.0±0.38	2.4±0.29	11.0	1.84	0.21
30-May	F	2.8±0.18ab	2.4±0.22ab	2.2±0.11b	3.1±0.11a	10.4	4.35	0.04*
2-Jun	F	3.1±0.36	3.8±0.47	3.5±0.19	4.1±0.49	14.6	1.13	0.4
3-Jun	F	1.3±0.16	1.6±0.31	1.7±0.13	1.5±0.05	6.1	0.63	0.6
6-Jun	F	2.1±0.19	2.6±0.39	3.0±0.24	3.2±0.29	10.9	3.14	0.08
8-Jun	F	2.0±0.22	2.5±0.56	2.7±0.44	2.9±0.26	10.1	1.16	0.38
12-Jun	F	1.3±0.24	1.6±0.53	1.6±0.31	2.1±0.37	6.7	0.68	0.6
	F total	21.1	25.2	24.3	26.1	96.7
30-Jul	P	1.9±0.27b	2.4±0.19a	2.5±0.21a	2.1±0.12a	8.8	6.57	0.01**
1-Aug	P	0.9±0.22b	1.3±0.23ab	1.6±0.08a	1.9±0.2a	5.6	11.33	0.002**
7-Aug	P	1.3±0.29	2.0±0.33	1.7±0.1	1.4±0.17	6.3	2.2	0.16
	P total	4.1	5.6	5.7	5.4	20.7

Means in a row with followed by no letters or followed by the same letter are not significantly different (Tukey, P > 0.05)

* P < 0.05; ** P < 0.01

Table 4. Biweekly and season mean total harvest yields in lbs (±SE) per treatment plot of five Prime-Ark® Traveler blackberry plants during two cane production periods (F = floricane = earlier; P = primocane = later). Treatment plots (n=4) included: Sur = Surround whitewash; Sur+Cide = Surround whitewash + insecticide; Cide = insecticide; or Untrt = untreated plants. The F and P values were derived from log₁₀(x+0.1) transformed data from Tontitown, AR (2017)

		Berry yield (lbs)
Date	Cane type	Sur	Sur + Cide	Cide	Untrt	Row total	F_3,3	P > F
15-Jun	F	1.5±0.88	0.9±0.32	1.2±0.5	1.4±0.46	5.03	0.55	0.7
22-Jun	F	1.2±0.62	0.5±0.11	0.8±0.26	0.9±0.28	3.46	0.99	0.4
27-Jun	F	0.5±0.1a	0.3±0.04a	0.2±0.05b	0.3±0.05ab	1.34	8.84	0.005**
29-Jun	F	0.5±0.12	0.3±0.06	0.4±0.11	0.4±0.08	1.67	1.79	0.2
6-Jul	F	0.3±0.05	0.2±0.03	0.3±0.05	0.2±0.02	1.05	0.96	0.5
13-Jul	F	0.2±0.07	0.1±0.06	0.1±0.04	0.0±0.03	0.5	0.97	0.4
20-Jul	F	0.2±0.06	0.1±0.0	0.1±0.02	0.1±0.02	0.43	2.78	0.10
	F total	4.4	2.7	3.1	3.4	13.5
27-Jul	P	0.3±0.03a	0.2±0.04ab	0.0±0.02b	0.1±0.03ab	0.56	6.92	0.01*
3-Aug	P	0.2±0.09	0.2±0.05	0.1±0.03	0.2±0.05	0.64	3.17	0.08
10-Aug	P	0.2±0.09	0.2±0.03	0.2±0.06	0.2±0.05	0.75	0.31	0.8
17-Aug	P	0.3±0.04	0.4±0.08	0.2±0.07	0.3±0.06	1.19	1.44	0.3
24-Aug	P	0.3±0.12	0.4±0.05	0.2±0.08	0.3±0.06	0.99	1.97	0.19
31-Aug	P	0.3±0.17	0.3±0.07	0.1±0.02	0.1±0.02	0.87	3.29	0.09
14-Sep	P	0.9±0.07	0.9±0.03	0.14±0.1	0.05±0.03	0.38	0.51	0.7
	P total	1.6	1.6	0.8	1.1	5.4

Means in a row followed by no letters or followed by the same letter are not significantly different (Tukey, P > 0.05)

* P < 0.05; ** P < 0.01

Table 5. Twice weekly and season mean total harvest yields in lbs from 2-yr-old Prime-Ark® Traveler blackberry primocanes only by four treatment plots (n=4): Sur = Surround whitewash; Sur + Cide =Surround whitewash + insecticide; Cide = insecticide; or Untrt = untreated. There were no significant differences among four treatments (P > 0.05) in New Boston, TX (2018).

	Berry yield (lbs)
Date	Sur	Sur+Cide	Cide	Untrted	Row total
5-Jul	0.3	0.3	0.4	0.4	1.3
8-Jul	0.7	0.8	0.8	0.9	3.1
10-Jul	0.5	0.7	0.7	0.7	2.6
12-Jul	0.6	0.5	0.6	0.6	2.2
14-Jul	0.6	0.6	0.5	0.5	2.3
15-Jul	0.4	0.4	0.4	0.3	1.6
20-Jul	0.3	0.3	0.2	0.3	1.1
Season total	3.4	3.5	3.6	3.7	14.2

Table 6. Biweekly and season harvest total mean yields in lbs ±SE (n=4) from Prime-Ark® Traveler blackberry primocanes only by four treatment plots: Sur = Surround whitewash; Sur + Cide =Surround whitewash + insecticide; Cide = insecticide; or Untrt = untreated. There were no significant differences among four treatments (P > 0.05) in Tontitown, AR (2018).

	Berry yield (lbs)
Date	Sur	Sur + Cide	Cide	Untrt	Row total
Jul-30	0.06	0.09	0.05	0.07	0.3
Aug-6	0.35	0.28	0.23	0.34	1.2
Aug-10	0.47	0.64	0.49	0.27	1.9
Aug-14	0.45	0.54	0.33	0.33	1.7
Aug-17	0.15	0.15	0.08	0.14	0.5
Aug-21	0.41	0.16	0.26	0.25	1.1
Aug-24	0.21	0.13	0.14	0.11	0.6
Aug-28	0.21	0.15	0.12	0.12	0.6
Aug-30	0.17	0.11	0.17	0.09	0.5
Sep-4	0.39	0.19	0.3	0.25	1.1
Sep-7	0.14	0.12	0.13	0.13	0.5
Sep-11	0.11	0.13	0.18	0.15	0.6
Sep-14	0.07	0.07	0.04	0.05	0.2
Sep-19	0.11	0.09	0.11	0.13	0.4
Sep-27	0.16	0.06	0.04	0.06	0.3
Oct-4	0.06	0.01	0.04	0.03	0.2
Season Total	3.5	2.9	2.7	2.5	11.7

Objective 2. To demonstrate that high summer temperatures in the southeastern states can be managed with mineral particle films (kaolinite) sprays.

Canopy treatments include: 1) Sur = Surround® WP kaolin clay mineral particle film only applied weekly or as needed; 2) Sur + PM = Surround + pest management (PM) pesticide applied as needed plus conventional integrated pest management practices; 3) PM = PM treatment only; and 4) Untrt = untreated plants (check). Surround® WP was applied using a Stilh backpack airblast sprayer at a rate of 50 lb/acre to whitewash plants. Whitewash and/or insecticide residues were maintained by re-applying as needed after rains greater than 0.25”.

In 2017, the Tontitown planting had four WatchDog 1000 series loggers (4 replicates) each inside a radiation shield set at 1 m height next to the blackberry planting to record ambient air temperatures. Recordings were made at half hour intervals from May 22 (before first Surround application) to August 31 (end of harvest). Each logger recorded temperatures from two micro sensor gator clipped to underside of separate blackberry leaves at 0.1 m and two at 0.3 m height inside the canopy of each of the four treatment plots (fig. 1). Mean ambient air temperatures were compared to mean temperatures from inside the blackberry canopy whitewashed with either Surround (Sur or Sur + Cide) or a green canopy (Cide and Untrt).

Figure 1. Blackberry canopy whitewashed with Surround mineral particle film (kaolin clay).

The air temperatures (ambient) next to plants were slightly warmer (more degree-days accumulated, base 50°F) than those in the blackberry canopy at 1 or 3 ft heights with or without whitewash of Surround. There was no significant difference between temperatures inside the blackberry canopy on underside of leaf on plants whitewashed with Surround kaolin clay or unsprayed (green) (Fig. 2).

A difference comparison was made of temperatures of ambient air minus underside of leaves whitewashed with Surround for periods of no sun (night from 8pm to 7am) and sun (day = 7am to 8pm) (Fig. 3-5). During the day, the ambient air was frequently greater than the whitewashed canopy by 0 to 6°F (mean of 2°F) compared to 0 to 3°F (mean of 1°F) at night which showed the heating effect of sunlight on air and canopy temperatures.

Figure 2. Cumulative degree-days (base 50°F) of ambient air (blue line), leaf inside canopy whitewashed with Surround kaolin clay (gray line) applied on 8, 27 June, and 1, 22 July (black arrows) leaf in untreated green canopies (green line). Rain exceeding 0.5 inches fell on 18, 30 June and 7 to 8 July (blue arrows) near Tontitown, AR (2017).

Figure 3. Distributions of frequencies of differences in temperatures of ambient air - Surround whitewashed canopy of Prime-Ark® Traveler blackberry during A) daylight (7am-8pm) and B) night (8pm-7am) near Tontitown, AR (2017)

Figure 4. Daylight (7am-8pm) temperatures recorded at ½ hr intervals by WatchDog logger. Left y-axis values are for ambient air temperature in radiation shield at 3 ft height (purple dots, from micro sensors clipped to underside of leaf at 1 ft (black dots) and 3 ft (light blue dots) inside the canopy of Prime-Ark® Traveler blackberries and corresponding colored trend lines. Arrows note dates plants were whitewashed with Surround and tear drops note rainfall >0.25”. Right y-axis values are for lower blue dots and blue trend line are the differences between ambient air – inside Surround whitewashed canopy (Tontitown, AR 2017)

Figure 5. Night (8pm-7am) temperatures recorded at ½ hr intervals by WatchDog logger. Left y-axis values are for ambient air temperature in radiation shield at 3 ft height (purple dots, from micro sensors clipped to underside of leaf at 1 ft (black dots) and 3 ft (light blue dots) inside the canopy of Prime-Ark® Traveler blackberries and corresponding colored trend lines. Right y-axis values are for lower blue dots and blue trend line are the differences between ambient air – inside Surround whitewashed canopy (Tontitown, AR 2017)

Objective 3. To determine if mineral particle film sprays can provide protection from various insects and diseases.

Sanders at Gillam Farm, Kirkpatrick at Moss Springs, and Johnson at Sta-N-Step will monitor treatment plots and decide when growers should apply recommended conventional pest management practices (2015 Midwest Small Fruit and Grape Spray Guide; Anonymous, 2015). These pest management decisions will be made by plot: using biweekly monitoring of baited traps for spotted wing drosophila (SWD) flies, leaves for broad mites and spider mites, fruit clusters for stink bugs, general plant inspection for other insect pests; and record severity ratings for presence of anthracnose, cane blight, rosette, or other diseases. During weekly harvest, all berries per plot will be collected and inspected for presence/severity of anthracnose and grey mold, and note the percentage of berries infested by SWD.

Formulations of fungicides and insecticides and application dates are listed in Table 7. In New Boston, TX, the grower applied Bifenthrin or Ravage (Lambda-cyhalothrin) in 2017 or Malathion in 2018 for stink bugs. Near Tontitown, AR the grower used pto powered custom spray nozzles to apply fungicides to all blackberry plants for anthracnose control in 2017 and in 2018 and applied Imidacloprid for rednecked cane borer control in 2017. In Searcy, AR, a Stihl backpack airblast sprayer was used to apply fungicide to plots 2 (Sur + PM) and 3 (PM). Insecticide sprays against spotted wing drosophila were applied (re-applied after significant rainfall) to treatment plots 2 (Sur + PM) and 3 (PM) in 2017 and in 2018.

Results:

The insecticide applied to treatments 2 and 3 included: Malathion 1, 3 July; Mustang Maxx on 12 June, 19 July, 26 August, 11, 22 September; and Delegate on 1, 10 August. These insecticides were applied to prevent damage to flowers by Japanese beetles (JB), damage to ripening berries by green June beetles (GJB) in July and SWD from early-June through 4 October. In and around the blackberry planting, there were low, sub economic densities of JB adults in June and July (Table 8) and GJB adults in July (Table 9). The GJB adults were mass trapped using 17 bottle traps placed 5m apart on fence in perimeter and baited with paper wicked pouched dispensing 50% isopropanol that captured 4,907 GJB adults. In an adjacent Natchez blackberry row there were ripe berries being fed on by GJB adults even after weekly applications of Mustang Maxx. Johnson is still analyzing SWD fly counts that emerged from fruit harvested from 7 September to 4 October and tabulating data from Searcy, AR and New Boston, TX.

Table 7. Dates of pest management applications of fungicides and insecticides to blackberry plants in Arkansas and Texas.

	Searcy, AR		Tontitown, AR		New Boston, TX
	2017	2018	2017	2018	2017	2018
Fungicides
Lime Sulfur or SulfurX			Mar. 3	Feb. 28	Mar. 15
Pristine	May 31 June 17 June 22 June 27 July 8, 14, 24	May 25 June 11, 25 July 10, 23	Apr. 27 Aug. 17	Apr. 24
Captan			Apr. 7 May 15 June 18	May 8
Abound			May 25 June 6, 21
Insecticides
Imidacloprid^a			May 3
Ravage^b					May 7, 24
Malathion^c			June 22	July 1, 3		May 24
Mustang Maxx^c or Bifenthrin^bc			May 25 June 6 July 8, 18 Aug. 24, 31	June 12 July 8, 19 Aug. 1, 10, 26 Sep. 11, 22	17 July
Delegate^c			Aug. 7, 15 Sep. 10, 20	Aug. 1, 10
Entrust^c			July 24 Aug. 1

^aRednecked cane borer

^b Stink bug

^c Spotted wing drosophila

Table 8. Mean numbers of Japanese beetles captured in baited yellow funnel traps adjacent to two blackberry plantings in Northwest Arkansas (2018).

Date	Tontitown, AR	Date	Fayetteville, AR
15-Jun	290	19-Jun	975
18-Jun	389	22-Jun	888
25-Jun	238	25-Jun	388
27-Jun	969	27-Jun	1,388
2-Jul	1,881	2-Jul	1,831
4-Jul	3,475	5-Jul	350
10-Jul	2,038
16-Jul	2,231
23-Jul	2,656	25-Jul	4,463
30-Jul	3,144	1-Aug	800
6-Aug	919
13-Aug	300	14-Aug	369

Table 9. Mean per trap and total numbers of green June beetles captured in 17 baited (66% isopropanol) bottle traps set at 2 foot height on fence adjacent to blackberry planting near Tontitown, AR (2018).

Date	Mean/trap	Total
16-Jul	67	1068
23-Jul	127	2152
27-Jul	49	826
30-Jul	26	435
9-Aug	20	348
16-Aug	5	78

Number of farmers who participated in the research (3):

Les Dozier, participating blackberry grower near Tontitown, AR
Jeremy Gillam, Doug Gillam and Ritter Farm participating blackberry grower in Judsonia, AR
Eric Lum, participating blackberry grower in New Boston, TX

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.