Charcoal rot caused by Macrophomina phaseolina (Mp) has become a major threat to the California strawberry industry. We examined the effect of growing 'Summit 515' wheat as a precrop of strawberries with and without anaerobic soil disinfestation (ASD) on suppressing charcoal rot in strawberries. A series of pot experiments, replicated field trials on the Central Coast, and demonstration trials on commercial fields in the Southern Coast were conducted. Economic analysis using a partial budget was performed using data from the field trials. Growing wheat did not significantly reduce soil Mp populations, and growing and incorporating wheat failed to suppress charcoal rot in strawberries in a replicated field trial. In contrast, ASD applied within beds (bed-ASD) in a sandy loam demonstration trial and ASD applied on a flat ground (broadcast-ASD) in loamy sand replicated field trials suppressed charcoal rot in strawberries. However, the Mp populations in the soil were significantly reduced only in the demonstration trial. Potential mechanisms and cumulative Eh and cumulative soil temperature conditions required for those cases are discussed. In a clay loam demonstration trial, bed-ASD did not develop sufficient anaerobiosis and failed to suppress the disease because of large soil clods in the beds. A partial budget economic analysis indicated that broadcast-ASD may be cost-prohibitive, whereas the bed-ASD is more viable. Taken together, bed-ASD may be a viable option for suppressing charcoal rot in strawberries in sandy to loamy fields in the Southern Coast of California. Bed-ASD in fields with high-clay content soils remains challenging.[Formula: see text] Copyright © 2026 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

We appreciate Verteramo and Gomez’s Life Cycle Analysis (LCA) work on conventional and organic strawberry production systems in California [...]

In strawberry ( Fragaria × ananassa ), initial bare-root crown diameter and early-season flower cluster removal have been two factors suspected of influencing fruit yield and size. This study evaluated the effect of these two factors on the day-neutral strawberry varieties Monterey and Cabrillo. Bare-root crowns with three different diameters were categorized into small (< 0.5 cm), medium (> 0.5 to 1 cm), and large (> 1 cm) at planting. Each of the crown diameter treatments was split into two plots for flower removal or no flower removal in the early season and data on canopy diameter, fruit yield, and fruit size collected in the subsequent months of production. The study was conducted over two growing seasons (2019–20 and 2020–21). No difference was found in plant canopy diameters measured in February, ∼3 months after planting, between any of the treatments in either year. Although early-season flower removal and some crown sizes resulted in lower fruit yield in March and April, none of these treatments resulted in any fruit yield or size differences in subsequent months nor in season end totals.

The use of polyethylene (PE) mulch causes environmental pollution where incomplete removal leaves fragments susceptible to escape to ecosystems, such as the ocean, where they can cause ecological harm. PE mulch is generally nonrecyclable due to contamination with soil and crop debris after use, leaving growers with few end-of-life options for used PE mulch. Research studies have shown that soil-biodegradable plastic mulch (BDM) is comparable to PE mulch in terms of performance, soil health, and overall economics and is preferred from an environmental perspective, but the adoption of BDM by producers is still low. Previous research has shown that the primary barriers to BDM adoption are insufficient knowledge about BDM, high purchase cost, and unpredictable breakdown of BDM in the soil. The high purchase cost of BDM compared with PE mulch is offset by the costs for PE mulch removal, transport, and disposal fees. This project was conducted to develop BDM training materials, to educate and assess BDM knowledge gained by extension personnel and other agricultural professionals through trainings and webinars, and to educate producers about BDM through hands-on experience. Thirty-six research and extension publication outputs from two previous US Department of Agriculture Specialty Crop Research Initiative BDM projects were reviewed and transcribed into 45 new extension publications that included 11 slide presentations, 5 lecture slides, 10 fact sheets, and 3 videos. All the training materials are posted on a public university website. Professional development trainings were conducted at local, regional, national, and international levels to provide agricultural professionals the current, science-based information on BDM and resources for information. Survey results showed that at a local level, the greatest change of knowledge among participants was observed for “BDM use in organic production” (60%), and the lowest reported change of knowledge was observed for “limitations to PE mulch disposal” (19%). At a regional level, out of 58 participants, 23% to 35% of participants learned “a lot” and 35% to 51% learned “some new information” regarding BDM from the webinar. At the national level, out of 30 participants, 48% responded that they learned “a lot” and another 48% learned “some new information” on BDM from the training. Growers were trained about BDM via field days and on-farm demonstrations where five strawberry (Fragaria ×ananassa) growers volunteered to participate in BDM trials. The participant growers observed no difference in weed control and fruit yield between the PE mulch and the BDM. Growers expressed concerns about slow biodegradation of BDM after soil incorporation, potential impacts on soil biological activity, food safety concerns with BDM fragments and that BDM is not currently permitted for use in organic production.

Blackberry (Rubus fruticosus L.; Family, Rosaceae) is ranked within the top three and top 25 agricultural crops in Santa Cruz and Monterey counties in California (Central Coast), respectively. The value of blackberry in Santa Cruz Co. has been estimated at ∼ US$52.8 million and has been planted on 367.5 ha (Santa Cruz County Crop Report 2019), while it has been valued at ∼ US$13.5 million and grown on 91.6 ha in Monterey Co. (Monterey County Crop Report 2019). Blackberry is produced continuously from June to October on the Central Coast of California. The crowns of blackberry plants are perennial, and their canes bear fruits. Many arthropod pests pose a threat to blackberry, such as apple pandemis (leafroller), Pandemis pyrusana Kearfott; omnivorous leafroller, Platynota stultana Walsingham; orange tortix, Argyrotaenia citrana (Fernald); redberry mite, Acalitus essigi (Hassan); white apple leafhopper, Typhlocvyba pomaria Walh; rose leafhopper, Edwardsiana rosae (L.); spotted-wing drosophila, Drosophila suzukii Matsumura; and greenhouse whitefly, Trialeurodes vaporariorum (Westwood) (Bolda and Bettiga 2015, Univ. California IPM Pest Management Guidelines: Caneberries, UC ANR Publication 3437).In recent years, widespread incidences of deformed blackberry fruits have been reported in many blackberry production farms in the Central Coast of California (Fig. 1A). Blackberry fruit deformation can be caused by insufficient pollination after irregular wind, rain, and extreme temperature events (Martin et al. 2017, Compendium of raspberry and blackberry diseases and insects. APS Press, 83–85). Adults and nymphs of the western tarnished plant bug, Lygus hesperus Knight (Hemiptera: Miridae), have been regularly observed on blackberry canes during the fruiting season on many farms from the mid- to late-season (S.V.J. and M.B., unpubl. data). In strawberry (Fragaria × ananasa Duchesne), L. hesperus feeding injury to embryos affects the normal growth and development of tissues adjacent to the embryo (Handley and Pollard 1993, J. Econ. Entomol. 86:505–510) causing deformed or “cat-faced” fruits. Developing strawberry fruits, approximately 10 d old after petal fall, are particularly vulnerable to L. hesperus feeding injury (Bolda et al. 2008, Integrated pest management for strawberries, 2nd ed. University of California, Division of Agriculture and Natural Resources Publication 3351). However, it is not clear whether L. hesperus feeds on developing blackberry fruits and causes injury and fruit deformation. Thus, the objective of this study was to determine whether young developing blackberry fruits develop fruit deformation after exposure to L. hesperus adults.Experiments were conducted on blackberry cane “Prime-Ark 45” grown on a commercial farm in Watsonville, CA, in 2016. The canes on the farm were actively bearing flowers and fruits. The canes were grown in high tunnels and regularly irrigated. Adults of L. hesperus were field-collected using sweep nets from Brassica weeds adjacent to organic strawberry fields in Salinas, CA. They were temporarily maintained for less than 4 h at 21°C and 40% relative humidity in the laboratory in cages and used for the experiment on the same day. Blackberry fruits were individually selected on the canes and caged using a 14L × 11W cm sleeve mesh cage. All the selected fruits in the experiment were at the petal-fall stage (Fig. 1B). The experiment was conducted three times, referred to as trials 1, 2, and 3. For trials 1 and 2, the treatments were densities of 0, 1, 3, 5, and 10 L. hesperus adults per cage, and the treatments were replicated 15 times in a randomized complete block design. For trial 3, L. hesperus adult densities of 0, 3, 5, and 10 per cage were the treatments, which were replicated 10 times in a randomized complete block design. The fruits selected for various treatments within the block were not at fixed spacing because fruits at petal-fall stages were not available at regular spacing. Ten replications (blocks) were employed on a row of blackberry canes, and the remaining five replications were employed on the second row of canes. The selected fruits were caged with sleeve mesh cages, and the densities of L. hesperus adults (treatment) were introduced. The L. hesperus adults were sorted into various aspirator plastic containers for each treatment. The treatments were employed up to 18.2 m deep into the high tunnel from the edge. The L. hesperus adults were exposed to fruits for 24 h and were removed using aspirators after 24 h. The cages were restored after adult removal to prevent access of naturally occurring L. hesperus on the farm to the treatment fruits. The fruits in various treatments were evaluated 3, 5, and 2 wk after adult removal for trials 1, 2, and 3, respectively. The fruits were evaluated for any deformation, as shown in Fig. 1A, and nondeformed fruits were quantified. The L. hesperus adults were removed on 15 June, 26 July, and 6 September for trials 1, 2, and 3, respectively. The blackberry fruits were removed from the canes and evaluated on 5 July, 30 August, and 19 September for trials 1, 2, and 3, respectively. The temperature loggers (EL-USB-2, Lascar Electronics, Inc., Erie, PA) were placed in the high tunnel at 18.2 m at 4.6-m intervals, and the average temperature in the high tunnel was 19.8°C for all three trials. For trial 2, the weight (g) and length (mm) of the fruits were measured. These measurements were not evaluated in trials 1 and 3. Categorical data and the number of nondeformed fruits were analyzed for treatment effects using nominal logistic regression (JMP Pro 15, SAS Institute 2019, Cary, NC). The L. hesperus treatments were compared by examining the odds ratio between two treatments; that is, probabilities of finding the number of nondeformed fruits were compared between two treatments by examining a χ2 value of odds ratio (P < 0.05). For trial 2, the data on the weight and length of the fruits were subjected to one-way analysis of variance (ANOVA) using the general linear model procedure (PROC GLM) in SAS (SAS Institute, Inc.) after log transformation (ln[x + 1]). The means were separated post-ANOVA using the Tukey HSD method (α = 0.05).The results showed that the number of marketable fruits was not significantly different among the L. hesperus treatments in trials 1 (χ2= 4.1; df = 4; P = 0.306; Fig. 2A), 2 (χ2= 8.2; df = 4; P= 0.085; Fig. 2B), and 3 (χ2= 5.0; df = 3; P= 0.169; Fig. 2C). For trial 2, the weight (g) of the fruits was not significantly different among the (F = 1.3; df = 4, 47; P = 0.269) following density treatments: 0 (mean ± standard error [SE] = 1.24 ± 0.24 g; n = 13), 1 (mean ± SE = 1.23 ± 0.33 g; n = 14), 3 (mean ± SE = 0.93 ± 0.29 g; n = 13), 5 (mean ± SE = 0.53 ± 0.13 g; n = 13), and 10 (mean ± SE = 4.13 ± 1.85 g; n = 12). The lengths (mm) of the fruits were significantly lower in the 10 adult treatment (mean ± SE = 5.3 ± 1.1 mm; n = 12) than in the 0 (mean ± SE = 14.2 ± 1.84 mm; n = 13), 1 (mean ± SE = 13.4 ± 2.0 mm; n = 14), and 3 density treatments (mean ± SE = 11.5 ± 1.86 mm; n = 13) (F = 4.4; df = 4, 47; P= 0.004). There was no difference in the lengths of the fruits among the 0, 1, 3, and 5 adult treatments. Thus, the results did not conclusively suggest that deformation of blackberry fruits was caused by L. hesperus adults feeding during production in the high tunnel. More research is warranted to determine the influence of other factors, such as extreme temperatures and wind velocity leading to improper pollination resulting in fruit deformation.We thank J. Martinez, D. Zavala, N. Zavala and E. G. Bejarano for the help with field collection of L. hesperus, deployment of cages, and damage evaluation of blackberry fruits. We appreciate the blackberry grower for providing access to his farm to conduct the experiments.

Insect activity, survival, and development are affected by climatic conditions that elicit effects at multiple scales. Pruning small fruit crop canopies alters the microclimate, which in turn may influence insect pest activity. We investigated the effect of three canopy density treatments (high, medium, low) on Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) fruit infestation in blueberries and caneberries using a two-year, multistate experiment. We quantified the effect of canopy density on canopy microclimate, fruit quality (total soluble solids, fruit firmness), and yield. To better understand heterogeneity in canopy microclimate, parameters were further separated by canopy location (exterior vs. interior) in Maryland. In both crops, meta-analyses reveal small magnitude effects of the plant canopy on microclimate, whereas analysis of variance did not separate these effects, with mean canopy differences of 0.1-0.7 degrees C and 0.5-1.3 % relative humidity (RH) between caneberry canopy densities and locations. In caneberry multi-state trials, 0.14 fewer D. suzukii larvae (g fruit)(-1) occurred on average in the low canopy density treatment, and 0.2 fewer D. suzukii larvae (g fruit)(-1) occurred in exterior raspberries in Maryland compared with the canopy interior. Artificially infested blueberry fruit indicated immature D. suzukii survival within fruit can vary across canopy densities and locations. Although lower total yield was produced in low density canopies, canopy density did not influence berry quality or marketable yield. Microhabitats provide important shelter from extreme environmental conditions; the availability of shelter and ability to locate it affects insect pest populations and distributions. Understanding how crop canopy microclimate affects D. suzukii infestation can inform efforts to develop habitat manipulation tactics and improve the efficiency of fruit production.

Western tarnished plant bug, Lygus hesperus Knight (Hemiptera: Miridae), is a serious insect pest of strawberry in California. Several effective insecticides are applied to manage L. hesperus in strawberry. These insecticides can induce behavioral changes to L. hesperus oviposition such as deterrence and avoidance which are poorly understood in strawberry production. This information can improve integrated L. hesperus management. The objectives of this study were to determine oviposition behavior of adult L. hesperus under 1) no-choice experiment with no insecticide-treated strawberry plant, 2) no-choice experiment with sulfoxaflor, flonicamid and novaluron-treated strawberry plant; and 3) choice experiment with non-treated and sulfoxaflor, flonicamid and novaluron-treated strawberry leaf petioles in semi-field settings. When the distribution of L. hesperus eggs within the non-treated strawberry plants were evaluated at upper, middle and lower strata of the plant as well as at various leaf parts, eggs were uniformly distributed along all three strata of the plant and most of the eggs were found on leaf petiole than on leaf blade, mid-rib or veins. In no-choice experiment, number of the eggs laid by the L. hesperus was significantly lower in the sulfoxaflor-treated than in the non-treated plants. In the choice experiment, number of eggs was significantly greater on non-treated petioles than insecticide- treated when the insecticide was novaluron. There was no difference in L. hesperus egg density between sulfoxaflor or flonicamid-treated and non-treated petioles.

Lygus hesperus Knight (Hemiptera: Miridae) is an important pest of strawberry in the central coast of California. Both adults and nymphs of L. hesperus feed on developing strawberry fruits causing cat-faced fruits (unmarketable). Although multiple tactics, such as vacuuming with tractor-mounted vacuum machine or the application of an insecticide, are used to manage L. hesperus, the combined effects of these tactics have not been thoroughly examined. Furthermore, the use of an electrostatic sprayer for L. hesperus management has not been tested. The objectives of the present study were to determine 1) the individual and combined effects of sulfoxaflor insecticide and vacuuming on L. hesperus and their feeding damage, and 2) the efficacy of sulfoxaflor when sprayed using an electrostatic sprayer at various rates of water volume against L. hesperus. The results showed that the vacuum alone did not reduce L. hesperus populations to untreated control (UTC). The treatments that involved sulfoxaflor, both individually and when combined with the vacuum reduced the number of L. hesperus and percentage cat-faced fruits compared to UTC. Neither the "bug vac" nor the sulfoxaflor had any impact on the capture of predaceous heteropterans and spiders compared to UTC. In various water volume treatments applied using electrostatic sprayer, the number of L hesperus nymphs and percentage of cat-face fruits was significantly lower than in UTC treatment and was comparable to conventional sprayer. The numbers of predaceous heteropteran and spider captures were not significantly different between the treatments applied using electrostatic versus conventional sprayers. These results implies that effective insecticide will continue to the best tactic to reduce L. hesperus and damage. Use of electrostatic sprayer has a potential whereas, vacuum method will need further refinement for L. hesperus control.

Red raspberry production in the western United States is heavily reliant on preplant soil fumigation to ensure the successful establishment and productivity of a planting. However, due to issues related to the regulation, availability, and economics of soil fumigation, alternatives are needed for current fumigation practices. Trials were conducted in commercial raspberry fields in California and Washington to evaluate alternatives to current fumigation practices in each region. In Washington, tarped bed fumigation with 1,3-dichlorpropene (1,3-D):chloropicrin (Telone C-35) performed as well as, and sometimes better than, the industry standard nontarped broadcast fumigation with Telone C-35 for the control of the soilborne pathogen Phytophthora rubi and the plant-parasitic nematode Pratylenchus penetrans. In one of the Washington trials, yield of raspberry grown in tarped bed-fumigated areas was 47% greater than the yield of plants grown in nontarped broadcast-fumigated areas. In California, a combination of chloropicrin:1,3-D (Pic-Clor 60) performed as well as the industry standard of methyl bromide:chloropicrin. Raspberry plants grown in soil fumigated with either of these fumigants were approximately 26% taller than plants grown in nonfumigated soil. Our results indicate that there are viable fumigation alternatives to the current fumigation systems used in Washington and California raspberry production systems.

The cover image, by Derek Farnsworth et al., is based on the Research Article Economic analysis of revenue losses and control costs associated with the spotted wing drosophila, Drosophila suzukii (Matsumura), in the California raspberry industry, DOI: 10.1002/ps.4497. Photo Credit: Kathy Keatley Garvey, Dept of Entomology and Nematology, UC Davis. image

BACKGROUNDThe spotted wing drosophila (SWD), Drosophila suzukii (Matsumura), is an invasive vinegar fly with a preference for infesting commercially viable berries and stone fruits. SWD infestations can reduce yields significantly, necessitating additional management activities. This analysis estimates economic losses in the California raspberry industry that have resulted from the SWD invasion. RESULTSCalifornia raspberry producers experienced considerable revenue losses and management costs in the first years following SWD's invasion of North America. Conventional producers have since developed effective chemical management programs, virtually eliminating revenue losses due to SWD and reducing the cost of management to that of purchasing and applying insecticides more often. Organic raspberry producers, who do not have access to the same chemical controls, continue to confront substantial SWD-related revenue losses. These losses can be mitigated only by applying expensive insecticides registered for organic use and by performing labor-intensive field sanitation. CONCLUSIONSWD's invasion into North America has caused extensive crop losses to berry and cherry crops in California and elsewhere. Agricultural producers and researchers have responded quickly to this pest by developing management programs that significantly reduce revenue losses. Economic losses are expected to continue to fall as producers learn to manage SWD more efficiently and as new control tactics become available. (c) 2016 Society of Chemical Industry

A trial comparing the efficacy of insecticide treatments against was conducted in a first-year planting of the strawberry variety ‘San Andreas’ in Watsonville, CA. Four replicates of each treatment were assigned to six 50-ft long 52-in. bed (with two plant rows per bed) according to a randomized completely block design. The details on insecticide products, rates, and application dates are shown in Table 1. First broadcast-spray of insecticide treatments was applied on 29 Jun 2016 followed by a second broadcast-spray application on 8 Jul 2016. The insecticides were applied using commercial tractor mounted sprayer. The water volume used for both the applications was 150 GPA and was applied at 140 psi. Dyne-Amic (surfactant) was added at 0.25% v/v to all treatments. View this table:Table 1. WTPB adults on strawberry treated with various treatments.Beat-trays were used to sample insect populations. Twenty strawberry plants were sampled between 11 AM and 2 PM from a plot and the sampling consists of five strikes per plant with the lid of a Rubbermaid container (14.9 × 12.2 × 6.7 in. [deep]). Sampling was done …

The fresh market berry industry in Santa Cruz and Monterey counties has contributed significantly to the agricultural vibrancy of the two counties and the state of California. Dramatic growth in strawberry, raspberry and blackberry production has been documented over the last 50 years, and most notably since the 1980s. Factors influencing this growth include innovations in agricultural practices and heightened consumer demand. Here, we review the historical context for the berry industry in Santa Cruz and Monterey counties. Organic production, production economics and challenges for the future are also discussed.

The western tarnished plant bug, Lygus hesperus Knight (Hemiptera: Miridae), is an important insect pest of strawberry (Fragaria ananassa Duchesne) in the Central Coast of California. Because little is known about efficacy of new insecticides, especially sulfoxaflor and flupyradifurone, against L. hesperus, two replicated insecticide experiments were conducted in 2014 and 2015 in commercial strawberry fields naturally infested with L. hesperus. The insecticides, sulfoxaflor, flupyradifurone, flonicamid, thiamethoxam fenpropathrin, essential oils (rosemary and peppermint oils), and mineral oil, were compared with untreated check. Higher and lower rates of flupyradifurone and sulfoxaflor were tested. Higher rates of sulfoxaflor and flupyradifurone were effective in suppressing L. hesperus. The industry standard, thiamethoxam + fenpropathrin, was effective in 2014 but not in the 2015 experiment. Flonicamid provided a moderate level of efficacy against L. hesperus in both years. The number of predacious bugs was significantly lower in the higher rate of flupyradifurone than in other treatments, although the number of spiders was not significantly different among treatments.

Spotted wing drosophila (SWD), Drosophila suzukii, exploded into California berry production districts in 2008 and cherry production districts in 2009 causing significant economic loss for a number of growers with many growers experiencing complete crop loss. Starting in 2009 in berries and 2010 in cherries the economic damage caused by D. suzukii was kept to a minimum through repeated applications of broad-spectrum insecticides. Insecticide usage increased 4.8 fold in cherry, 3.5 fold in raspberry and 1.2 fold in strawberry from 2007 to 2012. The repeated use of broad-spectrum insecticides disrupted integrated pest management systems developed for cherry and berry crops. The repeated application of insecticides has had a serious impact on the beneficial arthropods and has resulted in an increased use of miticides. Miticide use increased 2.0 fold in cherry, 3.8 fold in raspberry and 2.2 fold in strawberry from 2007 to 2012. Potential control options that would be less environmentally disruptive are biological control, cultural control, mass-trapping and attract and kill methods of control.

Anaerobic soil disinfestation (ASD), a biological alternative to soil fumigation, can control soilborne pathogens and nematodes in numerous crop production systems. To optimize ASD for California strawberries, a series of field and pot experiments have been conducted since 2003. Overall, ASD treatment was shown to be consistently effective at suppressing Verticillium dahliae and obtaining comparable yield with fumigant control in coastal California when 20 t ha(-1) of rice bran (RB) was pre-plant incorporated and at least 75 mm of irrigation was applied in sandy-loam to clay-loam soils. However, due to economic and high nitrogen application issues associated with use of 20 t ha(-1) RB, there is interest in examining alternative C sources used in ASD. In the 2012-2013 season, we conducted non-replicated demonstration trials at 4 local farms in which sugarcane molasses (Mol) 20 t ha(-1) alone or in combination with RB (Mol 10 t ha(-1) + RB 10 t ha(-1)) were tested. Although Mol has advantages over RB in terms of ease of application and lower N content, the anaerobic condition created by Mol did not last long and split applications were needed. Further, cumulative marketable fruit yield from Mol 20 t ha(-1) plots were as low as 70% of fumigated controls, whereas RB 20 t ha(-1) and Mol 10 t ha(-1) + RB 10 t ha(-1) plots had similar yields as the control. Lack of effectiveness in Mol-based ASD may be related to uneven distribution of Mol across the bed profile and low soil temperatures at trial sites. We also evaluated the potential for eliminating pre-plant fertilizer application when using RB-based ASD at one site. Pre-plant fertilizer increased fruit yield only similar to 5%, suggesting a possibility of reducing pre-plant fertilizer at ASD fields. Future studies should examine other C-sources including summer cover crops combined with a low rate of RB or Mol in ASD.

Native to Southeast Asia, Drosophila suzukii (Matsumura) prefer to oviposit on ripe fruit and have become an important pest of California raspberries (Rubus idaeus L.) since their detection in Santa Cruz County, CA, in 2008. Preliminary management guidelines included D. suzukii monitoring recommendations, though there was little available information on seasonal occurrence and potential lures for use in raspberries. To address this issue, we trapped adult D. suzukii weekly for 2 yr (including both spring and fall harvests) in multiple raspberry varieties using apple cider vinegar and a yeast-sugar-water mixture as liquid lures, and measured fruit infestation when commercially ripe fruit were available. D. suzukii pressure as measured by larval infestation and adult trap captures was higher during the fall raspberry harvest season. The yeast lure captured significantly more D. suzukii during the fall harvest than the apple cider vinegar, and while both lures tended to capture more females than males, this varied by month of the year and was more pronounced for the yeast lure. Trap captures from each lure correlated well to one another, and often exhibited significant correlation to larval infestation. However, during all seasons and under both conventional and organic management, worrisome outliers were present (high larval infestation with low trap captures) that call into question the reliability of using the systems presented here as a basis for management decisions at this time.

Organic strawberry/vegetable producers in coastal California face soilborne disease, nutrient, and weed management challenges. In conventional systems, stringent regulations and air quality concerns make the sustainability of fumigantdependent systems uncertain. To evaluate efficacy of anaerobic soil disinfestation (ASD), mustard cake (MC) application and broccoli residue incorporation, we initiated trials at an organic farm (Org) and a conventional farm (Conv) with crop rotation (broccoli (Brassica oleracea L. italica) - strawberries (Fragaria ananassa), cauliflower (Brassica oleracea L. botrytis) - strawberries, or fallow - strawberries) as main plot in June 2011. Sub plots (ASD, MC, ASD+MC, untreated control (UTC), and fumigant (Pic-Clor 60. Conv only)) were applied prior to strawberry in October 2011. Cover crop and lettuce (Lactuca sativa) were grown after strawberries at Org only. Marketable fruit yield, weed density, and disease level were monitored during the strawberry season and soil inorganic N dynamics for the entire period. ASD+MC and ASD produced similar fruit yields as fumigant at the Conv site. ASD+MC produced greater fruit yield than UTC and MC at both sites and ASD at the Org site. ASD and ASD+MC produced high inorganic N in the soil 2 to 3 months after application at both sites. This caused salt damage on strawberry during early growth especially at Conv which may have reduced fruit yields in both treatments. Verticillium dahliae population in soil at strawberry transplanting was less than 1 microsclerotia/g soil at both sites. However, V. dahliae infection on strawberry plants at the end of the harvest season in Org was reduced by ASD and ASD+MC suggesting that the mechanisms of yield increase by ASD involved disease suppression. Weed suppression by ASD and MC was limited. The effect of broccoli rotation in V. dahliae and weed suppression was also limited and no synergistic effect of broccoli rotation with ASD and MC was observed.

Beginning at least as early as 2005 and continuing through 2010, the California strawberry industry has suffered production losses caused by soilborne fungi not previously recognized as strawberry pathogens in California. The vast majority of these problems took place in fields that did not receive the traditional pre-plant fumigation treatment of methyl bromide + chloropicrin. These new disease developments have been consistently associated with two pathogens: Macrophomina phaseolina and Fusarium oxysporum f. sp. fragariae. Pathogenicity tests confirmed that these fungi caused symptoms similar to those observed in the field. Other experiments indicated that some strawberry cultivars are apparently less susceptible than others. Field trials using alternative fumigants provided some control of both diseases. In California, both Fusarium and Macrophomina are appearing in previously uninfested areas, indicating that these pathogens will be long-term concerns for this industry.