To investigate the effects of night-time temperature on cell and fruit size, and sugar accumulation in watermelon fruit, fruits were treated with high night-time temperatures in a greenhouse. The minimum night-time ambient temperature of the heating box (18°C) was approximately 6°C higher than that of the control. The length, diameter and weight of heat-treated fruit at the end of heating treatment, 16 days after anthesis (DAA), were significantly greater than that of control fruit, but those at harvesting, 42 DAA, were almost the same in both treatments. Mean cell size of the outer portion of heat-treated fruit at 16 DAA was significantly larger than that of the control. Cell size of the fruits at 42 DAA did not differ between heat-treated and control fruits. Sucrose, glucose and fructose content of fruit at 16 DAA did not differ between heat-treated and control fruit. However, sucrose content of the outer portion of heat-treated fruit was 162% of that of control fruit at 42 DAA. Glucose and fructose contents at 42 DAA did not differ between heat-treated and control fruit, except glucose content of outer portion.

To determine the relationship among cell size, acid invertase (AI) activity, sucrose phosphate synthase (SPS) activity, and sucrose accumulation in melon (Cucumis melo L.) during early development [from 6 to 16 days after anthesis (DAA)], fruit were heated at night to a minimum of 20 °C. Cells of heated fruit were larger than those of control fruit at 16 DAA but smaller at 50 DAA. AI activity was lower and SPS activity was higher in heated than in control fruit up to 26 DAA. Sucrose, glucose, and fructose contents at 26 and 50 DAA were higher in heated than in control fruit. Heating caused cells to reach mature size earlier than those of control fruit, and maturity was accompanied by earlier decline in AI activity and an earlier increase in SPS activity that promoted soluble sugar accumulation.

The effects of deficit irrigation and reflective mulch were studied as possible means to reduce irrigation water use and improve peach fruit quality and storage ability. 'Royal Glory' peach and 'Caldesi 2000' nectarine trees were drip irrigated close to ETc (control) or with 50% of ETc (deficit) during the last three weeks before anticipated harvest of tree-ripe fruit. Reflective Extenday mulch was also applied on the tree row for almost a month before anticipated harvest at control or deficit irrigated trees. Fruit quality from the upper and lower parts of the tree was evaluated at harvest and after 2, 4 and 6 weeks at 2°C plus 1 day shelf life. Fruit quality included skin color, flesh firmness, specific conductivity and dry matter (DM), juice soluble solids content (SSC), acidity and total phenols (TP) and subjective evaluation of chilling injury (CI) symptoms (flesh leatheriness and browning). With storage time and in both cultivars, fruit skin only slightly changed, fruit flesh softened, specific conductivity, SSC, acidity and DM decreased and TP content and CI (mainly leatheriness) increased. With deficit irrigation or reflective mulch, the two cultivars behaved differently. Nectarines from deficit irrigated trees had improved quality but lower storage ability than fruit from control trees. Peaches from deficit irrigated trees had similar quality to control fruit except of higher SSC (mainly the fruit from the lower part of the canopy) and slightly higher CI. Nectarines from reflective mulched trees had better skin color, harder flesh, higher acidity and DM, similar SSC and TP and higher leatheriness incidence than fruit from control trees. Peaches from reflective mulched trees had the most advanced maturity fruit at harvest compared to the other treatments, and higher quality fruit but also lower storage ability than control fruit. In short, fruit quality of both cultivars studied was improved due to deficit irrigation or reflective mulching but their storage ability was reduced from these treatments.

Strawberry fruit are susceptible to microbial decay during post-harvest storage. To search for an effective alternative to currently-used fungicides for disease control, we investigated the effect of benzo-(1, 2, 3)-thiadiazole-7-carbothioic acid S-methyl ester (BTH) on fruit decay and the maintenance of quality in strawberries after harvest. Freshly harvested strawberry fruit were treated with 0 (control), 0.05, 0.20 or 0.50 g l–¹ BTH for 5 min. BTH treatment at 0.20 g l–¹ was most effective at inhibiting fruit decay in strawberry fruit during storage at 5°C, while quality parameters such as total soluble solids contents and titratable acidity were also maintained. Fruit treated with 0.20 g l–¹ BTH exhibited reduced microbial populations and higher activities of chitinase and β1,3-glucanase. However, treatment with 0.50 g l–¹ BTH was ineffective at controlling fruit decay. Our results show that a post-harvest application of an appropriate concentration of BTH treatment was effective in reducing fruit decay and enhanced disease resistance in strawberry fruit. The data obtained suggest that BTH may provide an alternative to control post-harvest decay in strawberry fruit.

We examined, over the postharvest seasons of 2005-2007, regulated deficit irrigation (RDI) for its potential of saving water and maintaining fruit yield and quality in ‘Summit' sweet cherry. The postharvest irrigation treatments were: full irrigation (Control), receiving 80% of water in Control (RDI-80%), and receiving 50% of water in Control (RDI-50%). Midday stem water potential (Ψstem) was used for assessing plant water status. In 2006, trees produced a large crop and commercial fruit thinning had to be applied, whereas 2007 was a low crop year. The RDI treatment, first applied in 2005, reduced fruit set in 2006 and also reduced root winter starch concentration. In 2006, fruit set was lower in RDI-50% than in Control. But fruit thinning had still to be done with the final yield being the same among treatments. In 2007, RDI-50% produced more fruit and higher yields than Control. Relationship between postharvest Ψstem and crop load in the following season varied according to the year. They were negatively correlated in 2006 and positively correlated in 2007. Fruit firmness did not vary with irrigation treatments in any of the years. Fruit soluble solid concentration (SSC) and fruit relative dry matter (RDM) for RDI-50% was the highest in 2006 when RDI-50% trees had the lowest fruit set. In 2007, SSC and RDM for RDI-50% were the lowest with the trees having the highest fruit set and crop load at harvest. This study indicates that RDI-50% firstly applied in an “off” year, after crop has been harvested, can maintain fruit yield at similar levels to fully irrigated trees while saving water by 45%. Correction of biennial bearing and partial saving of thinning costs are additional advantages of this treatment.

In previous experiments, we identified that a postharvest curing treatment (50°C for 2h and 95-99% RH) satisfactorily controlled brown rot on several peach and nectarine varieties. In the present complementary study, the effect of fruit maturity, fruit with natural infection, time of infection and inoculum concentration on the curing efficacy was investigated. Different maturity levels affected curing efficacy. As fruit maturity increased, the efficacy of a postharvest curing treatment decreased from 95% control of brown rot (harvest mature fruit) to 65% (the most advanced mature fruit). The effect of Monilinia fructicola infection time prior to treatment also affected the curing efficacy. When the infection time was increased from 0 to 48h, brown rot control decreased from 90% to 64%. A factorial experiment design was used to investigate the effect of M. fructicola conidial concentrations (10³, 10⁴, 10⁵ and 10⁶ conidiamL⁻¹) at different exposure times (1, 2, 3 and 4h) on curing efficacy. Overall, longer curing exposure times (3 or 4h) were required when higher conidial concentrations were applied to the wounded fruit. At the lowest M. fructicola conidial concentration tested (10³ conidiamL⁻¹), 2h of curing exposure resulted in 100% and 94% brown rot control in ‘Andros' peaches and ‘Flames Kid' nectarines, respectively. A high level of brown rot control was also achieved when naturally infected fruit with Monilinia spp. were cured. When fruit with natural inoculum were surface sterilized prior to the curing treatment, complete brown rot control resulted. This findings support our earlier demonstration that a postharvest curing treatment is an attractive non-chemical strategy for use in conventional and organic stone fruit brown rot management.

Significance of fruit flies in vegetable crops. Vegetable crops hold a key position in agricultural production in Reunion (Indian Ocean); however, many pests and diseases threaten the profitability of this agricultural sector. Fruit flies (Diptera: Tephritidae) figure among the main pests for solanaceous crops and cucurbits (cucumber, zucchini, melon, etc.). Losses of as much as 80% of tomato and 100% of cucurbit crop harvests have been frequently observed. Inventory and distribution. Four fruit fly species belonging to the Tephritidae family cause major damage to vegetable crops in Reunion: Bactrocera cucurbitae (Coquillet), Dacus ciliatus Loew and D. demmerezi (Bezzi) on Cucurbitaceae, and Neoceratitis cyanescens (Bezzi) on Solanaceae (primarily the tomato). Distribution of each of them is presented. Biology and behavior. A few studies on the biology and behavior of the four fruit flies were conducted in Reunion in the late 1990s. Their main biological characteristics are summarized. Population control methods used in Reunion. Various methods such as chemical control, preventive measures (sanitation), physical control, biotechnical control [colored traps, the Male Annihilation Technique (MAT) and the Bait Application Technique (BAT)], and biological control currently used in Reunion against fruit flies are reported. Other control methods such as Integrated Pest Management and the Sterile Insect Technique are not used in Reunion. Prospects for implementing agro-ecological management of vegetable fruit flies in Reunion. This part presents research actions implemented in fly bio-ecology, research actions into the genetic structure of populations and design of an agro-ecological management scheme for vegetable fruit flies. Conclusions. The control methods used independently have not been successful to effectively control tephritid populations. A more integrated approach is required, also taking into account the landscapescale and its mosaic of habitats, especially wild plants, whose role must be considered within a framework of agro-ecological management of these pest populations.