The olive fruit fly, Bactrocera oleae (Rossi), is the most economically important pest of the olive tree; the fly prefers some cultivars over others, although the reason for this is still unclear. Current research results indicate that volatile compounds of the olive tree have a greater influence on the fly's attraction to a host plant than the physical parameters of the olive fruit. Therefore, the aim of the study was to investigate the relationship between the degree of the olive fruit fly infestation and the volatiles released by the olive leaves and fruits of three cultivars with similar physical fruit parameters, grown in the same olive grove. Lastovka, Frantoio and Leccino cultivars were studied, HS-SPME/GC-MS was performed to determine the profile of volatiles in leaves and fruits and to investigate the relationship between volatiles and the olive fruit fly infestation. Frantoio was the olive cultivar with the highest infestation by the olive fruit fly (39.66 %), followed by Leccino (24 %) and Lastovka (5 %). Among total number of volatiles identified in the study (55), more were detected in the fruits (37) than in the leaves (26). Saturated hydrocarbons and terpenes were the most abundant volatile groups in the fruits, while terpenes were found the most abundant in the leaves. The amounts of (E)-4,8-dimethylnona-1,3,7-triene E )-4,8-dimethylnona-1,3,7-triene and heneicosane were highest in the olive fruits of all cultivars tested. Heneicosane and eicosane were mainly released from ripe fruits and strongly correlated with the degree of infestation with the olive fruit fly. In addition, henicosane was the most abundant volatile compound in ripe fruits, along with 2,6-di-tert-butyl-4-methylphenol. Therefore, the results of the study suggest that fruit-derived volatiles have the greatest impact on the attraction of the olive fruit fly. The use of plant volatiles as attractants could be an effective tool for the sustainable control of olive trees to reduce the damage caused by the olive fruit fly while avoiding negative impacts on the environment and biodiversity.

Two bacteria belonging to the Pseudomonas and Pantoea genera were isolated from olive knots. Both bacterial strains were omnipresent in this study’s olive orchard with high susceptibility of the autochthonous olive genotypes indicating coevolution of bacteria with host plants. Genomes of two endemic bacteria show conserved core genomes and genome plasticity. The Pseudomonas ST1 genome has conserved virulence-related genes including genes for quorum sensing, pilus, and flagella biosynthesis, two copies of indole acetic acid biosynthesis (IAA) operons, type I-VI secretions systems, and genes for alginate and levan biosynthesis. Development of knots depends only on the presence of the Pseudomonas ST1 strain which then allows Pantoea paga strain co-infection and cohabitation in developed knots. The two bacteria are sensitive to a large number of antimicrobials, antibiotics, H2O2, and Cu (II) salts that can be efficiently used in propagation of bacterial free olive cultivars.

Sensory quality is of increasing importance to consumer decisions in choosing a product, and it is certainly an important factor in repurchasing in terms of meeting the necessary aroma quality and taste properties. To better understand the effects of rootstocks and scions on fruit quality, the sensory profile and volatile aroma composition of the fruits of hydroponically grown tomato plants were evaluated. Experiments were established using the tomato cultivars Clarabella and Estatio as scions during two spring-summer seasons. In both experiments, the scion plants were self-grafted or grafted onto rootstocks of cultivars Arnold, Buffon, Emperador, and Maxifort, with the exception that in experiment 1, the Estatio scion was not grafted onto Buffon. The scions and rootstocks caused differences in observed sensory properties in both experiments. For most of the sensory traits, interaction effects between scion and rootstock were observed. Compared to those obtained from self-grafted Clarabella, the fruits obtained from Clarabella grafted onto Buffon in the first experiment and Clarabella grafted onto Arnold in the second experiment were sweeter by one measurement unit. The contents of seven aldehydes, six alcohols, five terpenes and two ketones were determined. A lower accumulation of total aldehydes, 22–45%, due to lower amounts of pentanal, (E)-2-heptanal and (E,E)-2,4-decadienal, was found in the fruits from plants where Estatio was rootstock compared with the other rootstocks treatments. Clarabella as a rootstock increased (Z)-3-hexenal + (E)-2-hexenal accumulation from 35 to 65%. Grafting Clarabella onto the tested rootstocks led to a change in the composition of volatile compounds, while differences between the combinations with Estatio as a scion were generally not recorded. Fruits from self-grafted Clarabella had higher (Z)-3-hexenal + (E)-2-hexenal concentrations than did fruits from Clarabella grafted onto Arnold (for 54%) and Emperador (for 68%), and in the second experiment, grafting onto all commercial rootstocks reduced (Z)-3-hexenal + (E)-2-hexenal concentrations, from 25 to 74%, compared to those from self-grafted Clarabella. Higher (+)-2-carene and (−)-caryophyllene oxide concentrations were attained in plants in which Clarabella was grafted onto Maxifort (by 56%) and plants in which Estatio was grafted onto Arnold (by 36%) compared to self-grafted plants. This study showed the possibility of altering the composition of volatile aroma compounds and sensory properties of tomato fruits by the use of grafting techniques.

The tobacco whitefly Bemisia tabaci is among the most damaging pests in greenhouse production of tomatoes. Insecticide resistance management of B. tabaci requires continuous improvement of non-chemical methods for pest control. The goal of this study was to test the effects of scion and rootstock cultivars on the population densities of B. tabaci adult and large nymphs (4th instar to pupae), in a hydroponically grown tomato crop. The experiment was conducted using tomato cultivars 'Clarabella' and 'Estatio' during the spring-summer season. The tomato plants were non-grafted, self-grafted or grafted onto the rootstocks of 'Arnold', 'Buffon', 'Emperador', and 'Maxifort'. A two-factorial experimental design was applied. Initially, 3 days after infestation (DAI), the scion of 'Estatio' was more attractive to adults of B. tabaci, while 6 DAI, this difference was no longer apparent. For both assessments, the number of pest adult individuals was lower when scions were grafted onto tested rootstocks. Thus, plants of non-grafted or self-grafted 'Clarabella' and 'Estatio' were more infested than the plants grafted onto the rootstocks. The density of large nymphs was higher on 'Estatio' than on 'Clarabella' at 54 DAI, while such a difference was not observed at 35 and 77 DAI. In terms of the rootstock effect, tomato grafting onto commercial rootstocks reduced nymphal populations in all three assessment periods. The differences among the rootstocks for nymphal population density were not confirmed. The results indicated that grafting tomato plants could be included in an integrated management strategy for B. tabaci.

The tomato is an important horticultural crop, the cultivation of which is often under influence of abiotic and biotic stressors. Grafting is a technique used to alleviate these problems. Shortage of water has stimulated the introduction of new irrigation methods: deficit irrigation (DI) and partial root-zone drying (PRD). This study was conducted in two spring–summer season experiments to evaluate the effects of three irrigation regimes: full irrigation (FI), PRD and DI on vegetative growth, leaf gas-exchange parameters, yield, water-use efficiency (WUE), nutrients profile and fruit quality of grafted tomatoes. In both years, the commercial rootstocks Emperador and Maxifort were used. In the first year, the scion cultivar Clarabella was grown on one stem and in the second year the cultivar Attiya was grown on two stems. Self-grafted cultivars were grown as a control. In both experiments, higher vegetative traits (leaf area and number, height, shoot biomass) were recorded in tthe plants grafted on commercial rootstocks. The stomatal conductance and transpiration rate were higher under FI. Under DI, transpiration was lowest and photosynthetic WUE was highest. Photosynthetic rate changed between irrigation treatments depending on plant type. In both years, the total yield was highest in grafted plants as result of more and bigger fruits per plant. In the 2nd year, grafted plants under FI had higher yield compared to PRD, but not to DI, while self-grafted plants did not differ between irrigation treatments. WUE was highest in DI and PRD treatments and in grafted plants. Leaf N, P, K and Ca was highest in tthe plants grafted on Emperador and Maxifort, while more Mg was measured in self-grafted plants. More Ca and Mg were recorded in tthe plants under DI and PRD. Fruit mineral concentrations were higher in tthe plants grafted on commercial rootstocks. Total soluble solids differed between irrigation regarding plant types, while fruit total acidity was higher in Emperador and Maxifort. In conclusion, our study showed that grafted plants could be grown under DI with minor yield reduction with 30–40% less water used for irrigation. Moderate DI could be used before PRD for cultivation of grafted tomato and double stemmed plants did not show negative effect on tomato yield so it can be used as standard under reduced irrigation.

The effect of nitrogen concentration and pot volume were studied on morphological traits of pepper and eggplant seedlings using an ebb & flow fertigation system. Four different nitrogen (N) concentrations (35, 70, 140 and 205 mg L-1 N) and pot volumes (35, 45, 60 and 80 mL) were used to investigate their influence on seedlings vegetative development. Seedlings with developed cotyledons were irrigated with the nutrient solutions for 24 h, and then kept dry for 48-72 h depending on seedlings stage. Our results showed that seedling height, number of leaves and leaf area were affected by both factors. The tallest pepper seedlings were obtained at N concentrations of 70 and 205 mg L-1 (23.67 and 23.51 cm, respectively), while pot volumes of 45 and 80 mL achieved the best result with both species. Seedlings grown in 80 mL pots had highest number of leaves regardless of N concentrations. However, when using N at 140 mg L-1, the number of leaves increased regardless of pot volume. Leaf dry weight and area of both species were increased by increasing N concentration and pot volume. An increase of pot volume from 35 to 80 mL had positive effect on leaf thickness in both species. Nitrogen concentration increase and pot volume decrease resulted in an increase of specific leaf area. Seedlings grown with N at 140 and 205 N mg L-1 had the highest chlorophyll concentration index on both species. Using a N concentration of 140 mg L-1 and a pot volume of 80 mL ensured best seedling development in pepper and eggplant.

For two years, the tomatoes (cv. 'Belle' and 'Clarabella'), ungrafted, self-grafted and grafted onto the 'He-man' rootstock, were grown under two irrigation regimes, i.e., partial-root zone drying (PRD) and fully irrigated (FI), to investigate whether grafting can alleviate drought stress and promote water-use efficiency (WUE). The grafted plants under the FI regime had the highest vegetative growth, which was the result of more leaves and greater leaf area and were only significantly different from the PRD grown ungrafted plants. The grafted plants had the highest yield as a result of the greater number of larger fruits and the yield did not differ between the irrigation treatments. No differences were found in the leaf NPK concentrations, while the Ca and Mg were higher under the PRD regime. The ungrafted plants under the PRD regime had the highest total soluble solids and acidity in the fruit juice. The grafted plants had a significantly higher WUE, more pronounced in the PRD regime. The different types of irrigation did not influence the vegetative growth and the yield in the greenhouse grown grafted tomato. The PRD and rootstock effects should be additionally investigated with deficit irrigation.

We report the genome sequence of a Pseudomonas sp. strain isolated from olive knot galls. The genome size is 6.101 Mbp with a G+C content of 58%. A total of 6,137 coding DNA sequences (CDS) were predicted, including 52 tRNA and 4 rRNA genes.

Here, we present the total genome sequence of Pantoea sp. strain paga, a plant-associated bacterium isolated from knots present on olive trees grown on the Adriatic Coast. The genome size of Pantoea sp. paga is 5.08 Mb, with a G+C content of 54%. The genome contains 4,776 predicted coding DNA sequences (CDSs), including 70 tRNA genes and 1 ribosomal operon. Obtained genome sequence data will provide insight on the physiology, ecology, and evolution of Pantoea spp.

Two experiments were conducted on hydroponic tomatoes to assess the effect of tomato rootstocks/grafting on Trialeurodes vaporariorum populations. In the 1st experiment, the rootstock cultivars Arnold, Buffon, Emperador and Maxifort were grown as nongrafted or grafted with the scion cultivar, Clarabella, while the scion Clarabella was grown as nongrafted or self-grafted. In the 2nd experiment, a new scion Estatio was introduced to check the response of different genotypes to grafting and their attractiveness to the pest. The scions Clarabella and Estatio were self-grafted or grafted onto the rootstock cultivars Arnold, Buffon, Emperador and Maxifort. A two-factorial experimental design with four replications was applied in both studies, and the tomatoes were artificially infested with T. vaporariorum. In the experiment lower population densities of T. vaporariorum adult and large nymphs were recorded on four rootstock cultivars compared to the densities on Clarabella. The cultivar Clarabella was characterised by the lowest contents of glucose and fructose in phloem sap and the most attractive cultivar to T. vaporariorum. This suggests the infestation by T. vaporariorum could lead to a decrease in these carbohydrates in leaves. The lengths, widths and surface area of T. vaporariorum were lower on nongrafted Clarabella compared to ones developed on Clarabella grafted onto Buffon. In the 2nd experiment, the adult and nymphal pest populations were decreased by grafting on rootstocks, while the effect of the tested scions was generally not significant. In conclusion, the use of tomato rootstocks could constitute a valuable tool in an integrated pest management strategy against the greenhouse whitefly T. vaporariorum.

The presence of olive moth (Prays oleae Bern.) and effectiveness of different control treatment against it has been conducted on 160 olive trees of Leccino variety in Istria, Croatia. The treatments were: dimethoate, Bacillus thuringiensis var. kurstaki (Bt), pyrethrins, consociation of olive and planted pyrethrum and control. Olive moth has been monitored weekly using pheromone-baited delta traps and different coloured sticky plates in 12 and eight monitoring. Moth's life stages (non-destroyed, destroyed eggs and larvae) has been counted in seven monitoring. The predator activity has been determined as the ratio of destroyed eggs in the total number of observed eggs on 50 randomly chosen samples of flowers and fruits. On pheromone traps, the maximum catch has been determined on May 15th on control, when maximum of moth's flight on control, dimethoate and pyrethrins treatments coincided in time. There were more adults detected on pheromone traps sticky traps (16.8 times over). With time, moth's first preference was red and then blue sticky plates. The highest number of eggs (non-destroyed and destroyed) has been found on dimethoate on May 15th (2.8 +/- 1.1 and 4.5 +/- 1.6) and June 18th (0.8 +/- 0.5) as a consequence of accidental high oviposition rate at dimethoate plots before treatment applications. The highest number of larvae were detected on control on July 2nd (2.0 +/- 0.7).