Berry Yield Research Articles

Chemical Composition and Physical Characteristics of Fruits of Two Cultivars of Blue Honeysuckle (Lonicera caerulea L.) in Relation to their Degree of Maturity and Harvest Date

The aim of study was to compare yield, fruit quality, chemical composition and fruits colour of berries of two blue honeysuckle(Lonicera caerulea L.) cultivars of Polish bred ‘Wojtek’ and ‘Brązowa’ collected at the beginning and at the end of harvest season,respectively. On average, ‘Wojtek’ yielded 1565 g per bush, whereas ‘Brązowa’ 1941 g. During the fruit ripening process, considerablechanges were found in the fruit colour. Fruits of both cultivars became darker and their colour changed from green and yellow to redand blue. With the changes in fruit colour, considerable changes in firmness also occurred. Fruit ripening reduced fruit firmness andpuncture resistance. For both genotypes, the berries of late harvest were bigger and richer in soluble solids and total polyphenol, however,they showed decreased firmness, lower acidity, and L-ascorbic acid content. Nevertheless the time of harvest, ‘Wojtek’ berries surpassed‘Brązowa’ fruit regarding soluble solids, titratable acidity and L-ascorbic acid content (for late-crop berries of both cultivars 14.1>12.6%,3.4>2.7 g citric acid 100 g1, and 76>56 mg 100 mL-1. Further, ‘Wojtek’ berries showed higher total polyphenol content (149.30 and183.66 mg∙100 g-1, for early and late ripening fruit, respectively) compared to that of ‘Brązowa’ (125.51 and 175.67 mg 100 g-1). Amongphenolics, anthocyanins made the substantial group ranging from 94.47 mg 100 g-1 (‘Brązowa’ berries of early harvest) to 141.96 mg 100g-1 (late ‘Wojtek’ fruit).

Host status and damage potential of Paratrichodorus renifer and Pratylenchus penetrans (Nematoda) to blueberry (Vaccinium spp.)

Stubby root nematodes (Paratrichodorus species) and root lesion nematodes (Pratylenchus species) have been found in root zone soil of blueberry plants in most blueberry-growing regions of North America. Relatively little is known, however, of the reproductive potential and damage caused by these nematodes to blueberry. We performed controlled inoculation studies in a greenhouse in order to assess population growth and damage caused by Paratrichodorus renifer and Pratylenchus penetrans on a range of blueberry cultivars, including representatives of Vaccinium corymbosum (four cultivars), V. angustifolium (one cultivar) and V. ashei (one cultivar). All tested blueberry cultivars were considered good hosts to P. renifer (reproduction factor (RF) values > 1.0) except V. ashei ‘Powderblue’ which was considered a poor host (RF = 0.2 and 0.1 for trials 1 and 2, respectively). Paratrichodorus renifer reduced root biomass of susceptible blueberry cultivars; however, this effect was not consistent across trials. Pratylenchus penetrans did not reproduce on any blueberry cultivars under greenhouse conditions. Population growth and damage caused by P. renifer on V. corymbosum × angustifolium ‘Chippewa’ was assessed using field microplots. Paratrichodorus renifer reduced berry yield, canopy volume and top dry weights two years after inoculation by 40, 25 and 25%, respectively. Our results clearly indicate that P. renifer population densities increase on V. corymbosum and V. angustifolium and the nematode is potentially damaging to blueberry.

Comparison of irrigation scheduling strategies for achieving water use efficiency in highbush blueberry

A glasshouse experiment was carried out to assess the feasibility of applying partial rootzone drying (PRD) to highbush blueberries (Vaccinium corymbosum). A subsequent field experiment was established to assess four irrigation strategies with the aim of improving water use efficiency in blueberry production. Applying PRD to plants during a glasshouse experiment reduced stomatal conductance without reducing plant water potential. Hindered by high rainfall, a physiological response to PRD was not repeated in field grown plants. However, irrigation scheduled using a Kc (crop coefficient) curve constructed from Food and Agriculture Organization (FAO) 56 guidelines and post-harvest regulated deficit irrigation (RDI) delivered annual water savings of 0.8 ML ha−1 and 1.3 ML ha−1, respectively, compared with a total 3.6 ML ha−1 applied using a ‘rule-of-thumb’ approach commonly adopted by Australian blueberry growers. These savings were achieved without reducing berry yield or quality. This study is the first to report on the feasibility of applying FAO 56 guidelines, RDI and PRD as strategies to maximize water use efficiency in highbush blueberry production.

Suppression of Monilinia Blight: Strategies for Today and Potential Fungicide Options for Tomorrow

Fungicide efficacy field trials were conducted in Nova Scotia and Prince Edward Island during the 2009 growing season to address concerns over: (i) the possible tolerance of the fungal pathogen [Monilinia vaccinii-corymbosi (Reade) Honey] causing Monilinia blight or mummy berry to presently registered fungicides; (ii) increasing scrutiny of specific fungicides by end users; and (iii) the challenge of trying to apply a curative fungicide in a timely manner after an infection period has likely occurred. Results indicated that the active ingredients propiconazole (Topas® and Orbit®), prothioconazole (Proline®), and penthiopyrad (LEM17) were very effective in suppressing Monilinia blight, tolerance to propiconazole did not appear to be present, and the use of multiple active ingredients with different modes of action and persistence also provided excellent suppression. In addition, the treatments had a profound influence on berry yield with the propiconazole, prothioconazole, and penthiopyrad treatments having berry yields that were 73.6, 111, and 112% greater than the untreated control, respectively, at the Nova Scotia site. However, these berry yield results need to be viewed with caution given the known suppressive attributes of some of these fungicides to other diseases present during Monilinia infection periods.

NARROW BAND REFLECTANCE MEASUREMENTS CAN BE USED TO ESTIMATE LEAF AREA INDEX, FLOWER NUMBER, FRUIT SET AND BERRY YIELD OF THE WILD BLUEBERRY (VACCINIUM ANGUSTIFOLIUM AIT.)

ISHS XXVIII International Horticultural Congress on Science and Horticulture for People (IHC2010): International Symposium on Berries: From Genomics to Sustainable Production, Quality and Health NARROW BAND REFLECTANCE MEASUREMENTS CAN BE USED TO ESTIMATE LEAF AREA INDEX, FLOWER NUMBER, FRUIT SET AND BERRY YIELD OF THE WILD BLUEBERRY (VACCINIUM ANGUSTIFOLIUM AIT.)

Plant Growth Promoting Rhizobacteria in the Management of Radopholus similis and Meloidogyne incognita in Black Pepper

Field trials were conducted in black pepper cv. Karimunda and Panniyur in 2010 - 2011 to assess the efficacy of Pseudomonas fluorescens (Pfbv 22) and Bacillus subtilis (Bbv 57) against Radopholus similis and Meloidogyne incognita in Kanyakumari and Dindigul districts of Tamil Nadu. Talc based formulations of Pfbv 22 and Bbv 57 were prepared and applied through soil @ 10 g individually and as consortium (Pfbv 22 + Bbv 57 each @ 5g) /vine in the fields naturally infested with the above mentioned nematodes. Efficacy of talc formulations was compared with the standard chemical, carbofuran. Growth and yield parameters of black pepper and nematodes infestation in roots and soil were assessed at harvest of the berries. Soil application of consortia formulation of Pfbv 22 and Bbv 57 at 10 g per vine significantly enhanced the growth and berry yield of vine and reduced the nematode population over untreated control in both cultivars.

Does Pollen ‘Neighborhood’ Affect Berry Yield In Lowbush Blueberry (Vaccinium Angustifolium Ait)?

Proximally growing individuals of wild, lowbush blueberry (Vaccinium angustifolium Ait.) vary widely in yield despite being grown under conditions in which environmental heterogeneity is minimized by cultivation practices. We recently established that the relative self-fertility of the bearing plant is a significant predictor of its outcross yield. Further, although the species has historically been characterized as largely self-infertile, we, and others, have documented large variation in this trait among individuals within fields, and, thus, relative self-fertility stands as a partial explanation of yield variation in addition to other genetic factors, such as significant general and specific combining abilities. Here, we extend our scope by experimentally addressing whether pollen neighborhood affects yield. Lowbush blueberry is not sown, rather individuals have colonized fields by natural processes. Commercial fields of lowbush are generally pollinated by rented honey bees, which tend to pollinate nearby flowers. Our hypothesis is that clones may have become situated in differentially suitable pollen environments, at least partly explaining yield differences. We identified two high and two low natural yielders from each of two managed fields and collected pollen mixes from five donors surrounding each (n = 8). Under field conditions, each recipient received four pollination treatments including its' own neighborhood and the other three donor neighborhoods within the same field. Results showed that one of the low producers in each field had significantly higher yields when pollinated by any but their own neighborhood, thus substantiating our hypothesis that pollen neighborhood has an effect on yield.

Assessment of grape yield and composition using the reflectance based Water Index in Mediterranean rainfed vineyards

In rainfed vineyards water deficits play a major role in determining berry yield and composition. Therefore, reliable indicators of vine water status might be of great value for the optimization of grape yield and quality. In the present study the feasibility of using hyperspectral reflectance indices related to plant biophysical properties at predicting berry yield and quality attributes in rainfed vineyards is assessed. The study was conducted on Vitis vinifera cv. Chardonnay in commercial vineyards in the D.O. Penedès region (Catalonia, Spain) over two consecutive years (2007–2008). Field measurements of fractional intercepted Photosynthetic Active Radiation (fIPAR), canopy reflectance, predawn water potential (Ψp) and the canopy to air temperature difference at midday (ΔTmidday) were conducted at the stage of veraison. Yield, Total Soluble Solids (TSS), Titratable Acidity (TA) and the ratio TSS/TA (maturation index, IMAD) were determined at harvest. Contrasted water availability among vineyards prompted considerable variation in berry yield and quality attributes. Across years, higher yield was accompanied by higher TA (r=0.59, p<0.01) and lower IMAD (r=−0.63, p<0.01) while no significant relationship was observed between yield and TSS. Yield was related to canopy vigor (fIPAR) in a variable extend: in 2007, yield was positively related to fIPAR (r=0.71, p<0.05) while yield was found to decrease along with increasing fIPAR in 2008 (r=−0.62, p<0.05). Contrastingly, NDVI provided consistent estimates of yield across years (r=0.57, p<0.05). These results suggest that NDVI might be more appropriate to characterize the effects of varying water availability on yield than fIPAR. In addition, yield was found to be related to ΔTmidday (r=−0.63 and r=−0.66, in 2007 and 2008, respectively). Accordingly, the Water Index (WI), an indicator of vine water status, provided robust estimates of yield across years (r=0.61, p<0.01). The strength of the correlation between NDVI and WI vs. yield suggests that yield was influenced by changes in both leaf area (intercepted light) and photosynthesis (stomatal aperture) in a variable extent according to the timing and severity of water deficits in the years of study. Berry quality attributes did not show significant relationships against fIPAR but were related to ΔTmidday. Accordingly, NDVI did not show significant correlation with berry quality attributes, while WI was found to be consistently related to TA (r=0.70, p<0.01) and IMAD (r=−0.71, p<0.01) across years. The results obtained suggest that the WI might provide reliable estimates of berry quality attributes in vineyards experiencing moderate to severe water deficits with potential application in precision viticulture activities such as selective harvesting according to grape quality attributes as well as for ripening assessment.

Effects of cultivar and egg density on a colonizing vine weevil ( Otiorhynchus sulcatus) population and its impacts on red raspberry growth and yield

Black vine weevil ( Otiorhynchus sulcatus) is regarded as a damaging pest of horticultural crops, yet empirical data about its population dynamics and effects on crop yield are largely lacking. This paper reports a four year (2007–2010) field study that simulated colonisation by O. sulcatus in a red raspberry ( Rubus idaeus) plantation comprising two cultivars (Glen Ample and Glen Rosa). The study tested whether adult O. sulcatus abundance was affected by cultivar or original egg distribution. Total population estimates were also made using mark and recapture methods. Finally, the effects of O. sulcatus on plant growth and berry yield were quantified. O. sulcatus abundance was significantly higher on Glen Ample than Glen Rosa, with the difference becoming even greater in 2009 compared to 2008. The abundance of O. sulcatus adults on particular plants was not related to original egg density. Mark and recapture based estimates suggested that the overall O. sulcatus population reached 3500 in 2008 and 44,100 in 2009. O. sulcatus abundance on plants was negatively related to plant height. Comparing plants with greatest and lowest O. sulcatus burdens showed that the heavily infested plants had lower shoot and root biomass in both Glen Ample (62% and 60%, respectively) and Glen Rosa (50% and 12%, respectively), significantly smaller berries (5.1 g and 2.8 g, respectively, in Glen Ample and 3.3 g and 2.7 g, respectively, in Glen Rosa) and smaller yields (2.93 kg and 0.99 kg in Glen Ample and 2.80 kg–1.71 kg in Glen Rosa, respectively). While cane fruits like raspberry were thought to tolerate O. sulcatus attack due to extensive root systems, this study suggests that damage can be extensive, particularly on cultivars such as Glen Ample.

Evaluation of cloudberry (Rubus chamaemorus L.) clones for selection of high-quality varieties

Two female and two male cultivars of cloudberry (Rubus chamaemorus L.) have previously been released as a result of clone evaluation at the Norwegian Institute for Agricultural and Environmental Research. Selection criteria have been number of pistils or stamens per flower, number of flowers and number of shoots per m2. Recently two groups of clones have been evaluated with the aim of finding new cultivars for release. The clones were collected at different locations in Norway, as well as in England and at Svalbard. Results from harvesting in 2005 to 2008 show large genetic variation in all evaluated traits and indicate good production potential for some of the tested clones. Previously released ‘Fjellgull’ and ‘Fjordgull’ are confirmed as stable and high producing. Of the clones evaluated for the first time, especially clone 102 and clone 306 are possible contenders for release. In addition to prior selection criteria based on berry yield, berry contents also have been analysed. The results indicate that clones with a northern origin have higher levels of total phenols, total anthocyanins and carotenoids than clones of a southern origin.

Dispatches

Dispatches

Formation of raspberry (Rubus idaeus L.) new cultivars yield in the Ukrainian Right -Bank Lisosteppe

The authors present the results of estimating seven raspberry cultivars - 'Novokutaivs'ka'(c), 'Phenomen' (c), 'Sanya', 'Perseya', 'Gusar', 'Kryepysh' and 'Strunka' - concerning their capability of forming yield depending on the cultivation year weather conditions. The cv 'Gusar' has been selected which had the highest yield of high-quality berries for two years of researches (2009-2010).

Chemical approaches to manage coffee leaf rust in drip irrigated trees

The purpose of this study was to assess the efficiency of chemical approaches to manage coffee leaf rust (CLR) in drip-irrigated coffee trees. Coffea arabica plants of the Catuai Vermelho IAC 144 cultivar were subjected to applications of protective and systemic fungicides from December 2000 to June 2006. The fungicide copper oxychloride was applied preventively in December, January, February and March. Foliar application of the systemic fungicide epoxiconazol was performed at predefined dates (calendar) and after ascertaining that CLR was present in 10% of plants. A fungicide + systemic insecticide (cyproconazol + thiamethoxam) was applied on the soil at the beginning of the rainy season. The results showed that a strategy based on two foliar application calendar for epoxiconazol at pre-determined times in December (0.6 L c.p.ha−1) and March (0.4 L c.p.ha−1) controlled CLR more effectively than four foliar application calendar for the protective fungicide copper oxychloride applied in December, January, February and March, at 3.0 kg c.p. ha−1, application on the soil of fungicide + insecticide (cyproconazol + thiamethoxam) at the beginning of the rainy season and sampling and decision-making with foliar application of the systemic fungicide epoxiconazol at 0.6 L c.p.ha−1 after ascertaining a 10% disease incidence. There was no significant difference in yield among the different strategies of fungicide applications across the six studied crops. The averages of coffee berry yield of all the treatments with fungicides either protective and or systemic were 30.80 (60-kg bags of processed coffee per hectare) which is 22.4% higher than the control treatment. In conclusion all the strategies can be used to control CLR including application of systemic fungicide after ascertaining a 10% disease incidence. The number of application of systemic fungicide epoxiconazol at 10% disease incidence was approximately 40% less than in a calendar system. This is the first report of the effective control of CLR with systemic fungicide epoxiconazol either spraying on the plants (performed at predefined dates or after ascertaining a 10% disease incidence) or through the application of cyproconazol on the soil in drip irrigation trees.

Effects of peat moss and sawdust compost applications on N2O emission and N leaching in blueberry cultivating soils

Upland blueberry (Vaccinium ashei Read.) requires acidic and organic matter rich soils for its cultivation. Recently, the raised bed cultivation system has widely been used for blueberry cultivation, but it has a potential to cause nitrogen (N) losses via leaching and nitrous oxide (N2O) emission especially with high rate of N application. We investigated the effects of organic amendments on N losses; via leaching ammonium () and nitrate () and N2O emission under acid soil conditions. The treatments were (i) ammonium sulfate application (AS), (ii) AS with peat moss (AS + PM), and (iii) AS with sawdust compost (AS + SD). A container (surface area: 47 cm × 40 cm = 0.188 m2) experiment to simulate raised bed cultivation system using an ochric Cambisol was conducted at Chiba University, Japan, during 2008 and 2009. A blueberry plant in each container received N fertilizer three times: 14.8, 23.8, and 14.8 g N m−2 in July 2008, March, and July 2009, respectively. Incorporation of peat moss and sawdust compost with ferrous sulfate effectively decreased soil pH to its optimal ranges (4.0–5.2) and resulted in increased growth and yield of blueberry (berry yield of 2009: 93, 285, and 348 g plant−1 in AS, AS + PM, and AS + SD treatment, respectively) due to increased soil porosity and consequently enhanced plant root biomass. Concurrently, the AS + SD treatment resulted in the least N losses, followed by AS + PM and AS treatment both through leaching and N2O emission. The emitted N2O amount over about two-year blueberry cultivation were 1.28, 0.80, and 0.58 g N m−2 for AS, AS + PM, and AS + SD treatments, respectively. These results indicated that application of organic amendments decreased N losses to the environment most likely due to increased plant N uptake, microbial N immobilization, and consequent reduction in nitrification, denitrification, and leaching.

Variations of yield and utilisation of bilberries (Vaccinium myrtillus L.) and cowberries (V. vitis-idaea L.) in Finland

So far, only rough estimates for the utilisation rates of wild berries in Finland have been available. One reason for this is that there has been a lack of empirical-knowledge-based studies concerning total yields of wild berries and their yield variations. This study had three aims: 1) total bilberry and cowberry yields of an average crop year were calibrated for different (abundant and poor) crop years using the inventory data on wild berries collected by the Finnish Forest Research Institute (1997–2008); 2) national utilisation rates of bilberries and cowberries were calculated for three different berry years 1997–1999; and 3) regional utilisation rates of these berry species were calculated for the year 1997. According to calculations, annual bilberry yields in Finland vary from 92 to 312 million kg. For cowberry, the range of variation in total berry yields is from 129 to 386 million kg. It was also found that approximately the same proportion of the total yield of bilberries (i.e. 5–6%) was collected between 1997 and 1999. Utilisation rates of cowberries were also quite constant varying from approximately 8% to nearly 10%. In 1997, bilberries and cowberries were utilised most intensively in the eastern parts of the country and in the Oulu-Kainuu region. The results of this present study describe the situation before the phenomenon of foreign pickers. It can be presumed that commercial wild berry picking by migrant collectors has so far affected both national and regional utilisation rates of wild berries.

Plant Growth Is Stimulated by Tea-seed Extract: A New Natural Growth Regulator?

Various plant extracts are being marketed claiming to enhance both crop yield and quality and being environmentally friendly. However, these claims are rarely documented by scientific data. In this study, we investigate the growth regulatory effect of Tea Seed Powder (TSP), a saponin-rich waste product from tea seed (Camellia sp.) oil production. The product was tested in various concentrations on Lemna growth and as a soil and spray application on growth of pot grown beet, mustard, oat, and barley. Finally, two treatments, 0.2 g TSP/L dry soil and weekly sprays with TSP solutions corresponding to 1.5 g TSP/m2, were tested for effects on strawberry yield. The results showed significant growth-enhancing effects on the sterile Lemna of ≈20% above control, demonstrating that the growth increase was a plant physiological response to TSP rather than an indirect effect of TSP affecting pests and diseases or improving nutrient uptake. Soil-treated, pot-grown beet, oat, and barley plants showed significant biomass increases in the range of 27% to 41% above control at concentrations of ≈0.3 g TSP/L dry soil, whereas increases of 14% to 26% were observed in plants sprayed with 0.15 to 1.5 g TSP/m2. Sprayed strawberries had a 38% higher berry yield compared with control plants in 2008, whereas no difference in leaf number and area, number of runners, and inflorescences were detected. In 2009, there were no significant observable differences between sprayed plants and controls. Soil-treated strawberry plants, however, showed a decrease in leaf number in 2008 and in strawberry yield in 2009. The study concludes that TSP has pronounced and direct physiological effects on plants, which can both increase and decrease growth and yield depending on the applied dose. The growth-enhancing effect could be used commercially to improve crop yield; however, because TSP is also known to be very harmful to earthworms, possible environmental effects of the use of TSP in agriculture and horticulture must be considered before use.

Use of Selenium-enriched Mustard and Canola Seed Meals as Potential Bioherbicides and Green Fertilizer in Strawberry Production

New plant-based products can be produced from seed harvested from Brassica species used for phytomanaging selenium (Se) in the west side of central California. Se-enriched seed meals produced from canola (Brassica napus) and mustard (Sinapis alba) plants were tested as potential bioherbicides and green fertilizers in strawberry production under controlled and field conditions for two seasons. Treatments consisted of adding each meal (containing 2.2 mg Se/kg dry mass) to the soil at rates equivalent to 0, 2, and 6 t/acre, respectively, 7 days before planting. In growth chamber studies, the highest rates of either meal lowered berry yields by a high of 30% compared with no application (control). Among the nutrient accumulation, berry Se, calcium (Ca), manganese (Mn), and zinc consistently increased with most Brassica meal treatments and most significantly with the mustard meal. In the field studies, mustard treatments lowered the emergence of summer-germinating and resident winter annual weeds more than canola and control treatments. Strawberry fruit yields increased with all Brassica treatments, except a 42% fruit yield reduction was observed at a 6 t/acre rate of mustard meal. Increases in fruit Se concentrations and increases in Ca, phosphorus, and Mn were often observed for all Brassica treatments. Amending soils with Brassica seed meals may have more practical viability in organic agriculture as a potential bioherbicide and green fertilizer.

The Influence of Planting Substrate on Yield of Seven Blueberry Cultivars

To obtain good yields, the highbush blueberry (Vaccinium corymbosum) needs special soil conditions with high organic matter content and optimal pH values, ranging from 4.8 up to 5.5. To create such conditions on an alluvial soil, with low humus content, poorly gleyed, an experiment was organized on the 3rd terrace of the Doamnei River, between 2005-2009 period, at the Research Institute for Fruit Growing Pitesti –Maracineni. The experiment had the following scheme: A Factor - cultivar, with seven graduations: a1- Simultan, a2-Delicia, a3-Lax, a4-Compact, a5-Augusta, a6-Azur a7-Blueray; B Factor - planting substrate, with 3 graduations: b1-5 kg peat+5kg manure; b2= 10 kg coniferous litter; b3= 5kg peat+5 kg manure+40 g sulphur powder; C Factor - experimental year, with 5 graduations (2005-2009). On average, for three planting substrates and the experimental period, Simultan cultivar, except Lax one, registered a significant increase by 14-214% in the number of flower buds per bush, and by 29-213% in number of flower clusters per bush, versus the others 5 studied cultivars. On average, for seven studied cultivars and experimental period the b1 and b3 fertilization treatments showed significant higher values on all studied fruiting indicators, versus b2 fertilization treatment. The treatment b1 registered a significant increase by 7% in number of fruits per bush and a significant decrease by 9% in average berry mass (g) versus b3 treatment. On average, for seven studied cultivars and three planting substrates the number of flower clusters per bush, the number of fruit per bush and berry yield per bush were significantly different from one year to the other over the whole experimental period.

EFFECTS OF PINE-NEEDLE AND COMPOST MULCHES AND WEEDS ON NITROGEN DYNAMICS IN AN ORGANICALLY-MANAGED HIGHBUSH BLUEBERRY FIELD

Weed control is a major challenge for organic growers and nitrogen (N) fertility can be unpredictable when using organic amendments. A project assessing the use of heavy application of various mulches (pine needles and diverse composts) for organically-managed highbush blueberry (HBB) and their impact on weed growth and N acquisition, HBB growth, leaf tissue N, berry yield and quality, and soil acidity, moisture, temperature, and mineral N dynamics was initiated in 2005. From this, results for soil mineral N dynamics and plant and weed N removal are presented and discussed. The experiment was located in an established field of 'Duke' HBB in the Annapolis Valley, Nova Scotia, Canada. The design was a randomized split-plot consisting of five blocks, four fertility and mulch treatments [no amendment, pine-needle mulch (PN), manure-sawdust compost (MC) and seafood waste compost (SC)] as the main plots, and two levels of weed management (+/- hand-weeding) as the split plots. Residual ('carry-over') effects of mulches one year after application were also examined. Results from the 2-yr study indicate that weeds were a significant competitor for soil mineral N, reducing soil N content by 71%. In addition, weed competition was shown to reduce HBB growth and fruit yield. There was no evidence of net N immobilization despite high C/N ratios of the PN (72:1) and MC (48:1). Elevated soil mineral N levels were maintained for the longest period under SC, while PN did not increase mineral N above control levels. Pine-needle mulch was found to be the best treatment for suppressing weed competition, although additional N nutrition is warranted.

Effect of production system and pruning on Aphis sambuci dynamics over time and on elderberry yield

AbstractIn a 2‐year study, elder aphid (Aphis sambuci) dynamics over time and berry yield were evaluated in two production systems (integrated and organic) and in two winter pruning treatments (trees pruned to four and eight scaffolds) in two black elderberry orchards in Hungary. In the organic production system, the first aphid colony was observed 1–2 weeks earlier (late‐March) in both years and locations compared to the integrated programme. The number of aphid colonies then increased until mid‐May in both years, reaching a maximum number of aphid colonies of 11.2 on 100 scaffolds in the integrated production system and of 38.9 in the organic programme. Then, the number of colonies decreased and reached a zero value at mid‐June in the integrated production system and 2 weeks later (early July) in the organic one in both years and locations. First autumn aphid colonies were observed in early September in the integrated production system but 2 weeks earlier (late August) in the organic one in both years and locations. The number of aphid colonies between mid‐April and mid‐June indicated a larger increase on trees pruned to eight scaffolds compared to trees pruned to four scaffolds. Both the total number of aphid colonies and the area under the aphid colony curves (AUACC) were significantly lower (P &lt; 0.001) in the integrated treatments compared with organic ones. Across all treatments, both measures were significantly lower (P &lt; 0.05) on trees pruned to four scaffolds compared with trees pruned to eight scaffolds. However, when the effect of pruning on the number of aphid colonies was analysed separately for integrated and organic plots, pruning caused significant differences in aphid colony numbers and AUACC in the organic plots. Berry yield was significantly higher (P &lt; 0.05) in the integrated treatments compared with the organic ones, but pruning showed no significant effect on yield. Overall, pruning to four scaffolds resulted in a lower aphid colony number in the organic production system compared to the integrated one. Thus, winter pruning may be useful as an aphid control strategy in organic elderberry orchards.