Program Faculty and Staff

Rhuanito S. Ferrarezi - Ph.D.
Research Associate Professor of Horticulture and Aquaculture
Email: rhuanito.ferrarezi@uvi.edu
Phone: 340-692-4086

Thomas Geiger
Research Analyst
Horticulture and Aquaculture
Email: thomas.geiger@uvi.edu
Phone: 340-692-4063

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Publications

2016

Edible-pod peas as high-value crops in the U.S. Virgin Islands.

Snow peas (Pisum sativum var. saccharatum) and sugar snap peas (Pisum sativum var. macrocarpon) are high-value crops typically grown in temperate regions. Temperature is the main limiting factor to growing edible-pod peas in warmer U.S states and territories. Ferrarezi et al. (2016a) evaluated edible-pod peas performance in tropical climates to make cultivar recommendations to farmers in the U.S. Virgin Islands based upon fruit yield. Trials were performed in two consecutive years (2014 and 2015), testing cultivars of edible-pod peas: three snow peas [‘Little Sweetie’ (LS), ‘Mammoth Melting’ (MM), and ‘Oregon Giant’ (OG)] and three snap peas [‘Super Sugar Snap’ (3S), ‘Cascadia’ (CA), and ‘Sugar Sprint’ (SS)] in a complete randomized block with four replications. ‘Little Sweetie’ produced the highest total fruit yield for the season (15,442 kg·ha-1) and MM (4,249 kg·ha-1) and SS (3,349 kg·ha-1) produced the lowest total fruit yield in Year 1 (p<0.0001). The same trend happened in Year 2, where LS (14,322 kg·ha-1) and 3S (12,511 kg·ha-1) were higher yielding and MM (4,582 kg·ha-1) and SS (1,929 kg·ha-1) also resulted in the lowest yielding cultivars (p<0.0001). ‘Mammoth Melting’ showed a percent marketable yield below 80% in Year 1 (p=0.0097, r2=0.5433) and Year 2 (p<0.0001, r2=0.8236). ‘Mammoth Melting’ and 3S cultivars produced the tallest plants in Year 1 (p<0.0001, r2=0.9371), while MM was significantly taller than the others in Year 2 (p<0.0001, r2=0.9888). As expected, sugar snap peas presented a sugar content 10% higher than snow peas (p=0.0018, r2=0.6283). The snow pea cultivars had longer mean fruit length (ranging from 81 to 86 mm) than sugar snap peas (ranging from 60 to 68 mm). The opposite trend occurred with fruit thickness; sugar snap peas averaged 28.5% thicker than snow peas. The snow peas presented a wider fruit but in general had lighter weights compared to the sugar snap peas. The shoot dry weight of SS was on average 78.5% smaller than MM and OG, resulting in poor performance due to small plant size. ‘Mammoth Melting’ and 3S had the lowest chlorophyll content compared to the other cultivars (p=0.009, r2=0.5473). Results of this experiment indicated that edible-pod peas have potential as a specialty, short-season, high value crop when grown in the cool-dry winter months of the U.S. Virgin Islands. Of the cultivars tested, LS was the highest yielding cultivar evaluated within the environmental and geographical conditions of this study for two consecutive years.

How to cite this study: FERRAREZI, R.S.; WEISS, S.A.; GEIGER, T.C.; BEAMER, K.P. 2016. Edible-pod peas as high-value crops in the U.S. Virgin Islands. HortTechnology 26(4). In press.

Evaluation of Six Edible-Pod Pea Varieties as a Potential High Value Crop for the U.S. Virgin Islands

Sensor-based irrigation in different sweet pepper varieties in the U.S. Virgin Islands.

Sweet peppers (Capsicum spp.) are widely produced in the Caribbean islands. Farmers usually water the plants without using the proper water management techniques. Soil-based monitoring systems can be used to improve water use efficiency and save water resources. Ferrarezi et al. (2016b) tested two soil VWCS to trigger irrigation (0.32 and 0.42 m3/m3) and six sweet pepper varieties (‘Aristotle’, ‘Declaration’, ‘Intruder’, ‘Jupiter’, ‘Colossal’ and ‘Vanguard’), in a CRD with three replications. When the soil VWC dropped below the thresholds, the irrigation was turned on for 1 min. The soil moisture sensors malfunctioned due to a defective internal part, not controlling the irrigation properly. Irrigations were turned on manually every other day. The two VWC treatments were averaged, resulting in six replications per variety. Total yield ranged from 13,514 (‘Declaration’) to 16,940 kg/ha (‘Vanguard’). However, the total and marketable yield did not differ among varieties (p>0.05). Anthocyanin at 67 days after transplanting (DAP) was higher on ‘Colossal’ (18.56 ACI) compared to ‘Vanguard’ and ‘Declaration’ (12 ACI on average) (p=0.0126). Leaf chlorophyll and fruit weight, width, length and sugar content at 95 DAP were not significantly different (p>0.05). Fruit hardness was higher on ‘Intruder’ and ‘Jupiter’ (1.2 kgf) and lower on ‘Colossal’ and ‘Vanguard’ (0.96 kgf) (p=0.0012). Based on our results, fully functional sensors are necessary to control irrigation properly. All six varieties presented high yield, being suitable for cultivation in the U.S. Virgin Islands.

How to cite this study: Ferrarezi, R.S., T.C. Geiger, and K. Cuffy. 2016b. Sensor-based irrigation in different sweet pepper varieties in the U.S. Virgin Islands. ASHS 2016 Annual Conference, August 8-11. Atlanta, Georgia.

Greenhouse production of slicing cucumbers in the U.S. Virgin Islands.

Cucumber is one of the major vegetables in greenhouse production. Little information is available regarding the cultivation of cucumbers in closed environment in the U.S. Virgin Islands. Geiger et al. (2016) evaluated the production of slicing cucumbers in greenhouse under different substrate VWC applied using low-cost open-source microcontrollers. We tested four cucumber varieties (‘Boa’, ‘Bomber, ‘Corinto’ and ‘Summer Dance’) and three substrate VWCs to trigger irrigation (0.24, 0.36 and 0.48 m3/m3), on a split-plot CRD and three replications. When the soil VWC dropped below the thresholds, irrigation was turned on for 1 min. The soil moisture sensors malfunctioned due to a defective internal part, not controlling the irrigation properly. Irrigation was controlled manually every other day. The three VWC treatments were averaged, resulting in nine replications per variety. ‘Corinto’ (22,436) and ‘Boa’ (20,000 kg/ha) total yield were higher than ‘Summer Dance’ (10,604) and ‘Mountie’ (10,435 kg/ha) (p=0.0001). Marketable yield was respectively 85%, 91%, 63% and 40% of the total yield (p<0.0001). Total number of fruits per plant were 9.6 for ‘Corinto’, 7.1 for ’Boa’, 4.7 for ‘Mountie’ and 3.8 for ‘Summer Dance’ (p<0.0001). Fruit width, hardness and sugar content were not significantly different (p>0.05). Fruits were shorter on ‘Boa’ (18.7) and ‘Corinto’ (19.7 cm) compared to ‘Mountie’ (24.2) and ‘Summer Dance’ (25.7 cm) (p=0.0180). Based on our results, fully functional sensors are necessary to control irrigation properly. ‘Corinto’ and ‘Boa’ are the recommended varieties for greenhouse cultivation in the U.S. Virgin Islands.

How to cite this study: Geiger, T.C., K. Cuffy, and R.S. Ferrarezi. 2016. Greenhouse production of slicing cucumbers in the U.S. Virgin Islands. ASHS 2016 Annual Conference, August 8-11. Atlanta, Georgia.

2015

Performance of nine butternut squash varieties in summer in the U.S. Virgin Islands.

Butternut squash (Cucurbita moschata) is a high value vegetable with similar flavor and texture to other Caribbean pumpkin (Cucurbita pepo) varieties. Geiger et al. (2015) evaluated the yield potential of nine butternut squash varieties on St. Croix, USVI. The experimental design was a complete randomized block consisting of nine cultivars (‘Waltham Butternut’ [WM], ‘JWS 6823 PMR’ [JW], ‘Metro’ [MO], ‘Hunter’ [HR], ‘Honey Nut’ [HN], ‘Nutterbutter’ [NB], ‘Tiana’ [TA], ‘Butterbush’ [BB], and ‘Pilgrim’ [PM]) with three replications. The field was prepared following standard cultivation practices (ploughing, harrowing, and rototilling). Squash were seeded on June 9, 2014 with 0.8 m in-row spacing and 1.5 m between rows for a total of 18,750 plants/ha. Plots were irrigated with 40 cm T-Tape and fertigated weekly using soluble 20-20-20 fertilizer at a rate of 100 kg N/ha. The first harvest was 71 days after planting (DAP) and final harvest was 98 DAP. All varieties had similar total yield (JW 7,294; TA 7,040; HN 6,529; WM 6,390; PM 5,626; NB 5,301; MO 5,296 kg/ha) except for BB (2,833 kg/ha) (p>0.05). The marketable fruit weight was not different among the nine varieties (p>0.05). HN had the highest sugar content at 11.7°Brix, followed by MO (8.0°Brix) and PM (7.2°Brix). All the other varieties presented the same brix, ranging from 4.7 to 7°Brix (p<0.0001). TA presented 50% more melonworm moth (Diaphania hyalinata) than the varieties WM, NB, HR and BB (p<0.05). HN had higher leaf miner (Liriomyza sativa) (48) than NB, PM, WM, JW (20-40), and BB. WM, JW, and BB were more tolerant to leaf miner than the other varieties (8-15) (p<0.05). Silverleaf disorder, induced by the silverleaf whitefly (Bemisia argentifolii), was higher on HN, BB and TA (4) than PM (1), not been found on the other varieties (p<0.05). JW had less powdery mildew than HR (p<0.05). Results indicate that all varieties except BB have potential as a high value vegetable crop for St. Croix, USVI.

How to cite this study: Geiger, T.C., K.P. Beamer, S.A. Weiss, and R.S. Ferrarezi. 2015. Performance of nine butternut squash varieties in summer in the U.S. Virgin Islands. HortScience 50(9): S336 (Abstr.).

2014

Cucumber cultivar study in the U.S. Virgin Islands.

Cucumbers (Cucumis sativus) are a valuable commodity throughout most of the Caribbean, including the U.S. Virgin Islands. Downy mildew, a foliar disease caused by the oomycete Pseudoperonospora cubensis is one of the most destructive pathogens of cucurbits. Cucumber growers in U.S. Virgin Islands observed disease in their crops. Nine cultivars of cucumber (slicing type) ‘Dasher II’, ‘Fanfare’, ‘Indio’, ‘Intimidator’, ‘Speedway’, ‘Stonewall’, ‘Thunder’, ‘SVR 3462’, and ‘SVR 4719’ evaluated for disease resistance and yields in the summer of 2013 at the UVI-AES (Nandwani et al., 2014). All marketable fruits were weighed to determine total yields for each cultivar. Three fruits of each cultivar were randomly selected at each harvest and measured to determine individual weight, length, and diameter. Once downy mildew infestation was significant, 50 leaves of each cultivar were randomly picked and analyzed using a disease severity assessment key. ‘Indio’ had the highest marketable yield (166.3 kg), followed by ‘Stonewall’ (159.8 kg) and ‘SVR 4179’ (148.7 kg). ‘Indio’ had the significantly lowest rating of downy mildew (2.69), followed by ‘Speedway’ (3.29) and ‘SVR 4179’ (3.31). Matching fruit qualities to downy mildew resistance, study shows the ‘Indio’, ‘Intimidator’, and ‘SVR 4719’ cultivars were found more suitable for U.S. Virgin Islands conditions.

How to cite this study: Nandwani, D., J.R. Williamson, S. Crossman, and V. Forbes. 2014. Cucumber cultivar study in the U.S. Virgin Islands. Proceedings of the Caribbean Food Crops Society 50:157-161 (Abstr.).

Yield of tomato cultivars grown in the organic management in the U.S. Virgin Islands.

Increasing food prices, food safety concern and environmental impact resulted more and more consumers seeking alternatives to conventional system of food production. Organic farming offers a welcome alternative as to bring benefits to make a positive impact on the environment, health, and future yields. Tomato (Solanum esculentum) is a highly valued vegetable and grown for fresh market in the United States Virgin Islands. Four cultivars ʻMountain freshʼ, ʻRed Defenderʼ, ʻSecurity 28ʼ and ʻDefiantʼ were grown under organic management system at Sejah farm, Kingshill, VI. The experimental design was a randomized complete block and three replications for each cultivar grown in the field. Nandwani et al. (2014) conducted two trials in fall 2012 and 2013. Data on plant height, fruit weight and marketable yield collected from eight harvests during the growing seasons. ʻMountain Freshʼ produced the highest marketable yield (2,282 g/plant, US#1 fruit) and ʻSecurity 28ʼ produced lowest (1,796 g/plant) marketable (US#1) fruits. ʻDefiantʼ produced highest number of total fruits (675) harvested, however, fruit size was smaller (Mountain freshʼ produced biggest fruit (142.6 g). Plant height was not significantly different in all four cultivars tested. All four varieties did set fruits under organic management system and were rated good or excellent in taste and flavor.

How to cite this study: Nandwani, D., S. Dennery, V. Forbes, and T. Geiger. 2014a. Yield of tomato cultivars grown in the organic management in the U.S. Virgin Islands. HortScience 49(9): S279 (Abstr.).

2013

The effects of preemeergence herbicides on the growth, yield and quality of transplanted watermelon.

Field studies were conducted twice at two sites in St. Croix, U. S. Virgin Islands by Napoleon-Fanis and Nandwani (2013) to determine the effectiveness of preemergence applications of bensulide and halosulfuron in transplanted watermelon (Citrullus lanatus). Bensulide and halosulfuron were both applied separately. Although bensulide caused up to 5% seedling stunting and halosulfuron caused up to 10% seedling stunting and discoloration, watermelon plants were fully recovered by week 8 after planting. Yields of all treatments were similar to that of untreated plots. Control of grasses like goosegrass (Galium aparine) and of broadleaf weeds like amaranthus (Amaranthus spinosus) was not found in treated plots. Weed species, weed densities and the percentage of weed control found in bensulide and halosulfuron treated plots were similar to non-treated plots. Watermelon fruits in both treated and non-treated plots had a sugar content 8.5°Brix, which indicates poor quality fruits.

How to cite this study: Napoleon-Fanis, V. and D. Nandwani. 2013. The effects of preemeergence herbicides on the growth, yield and quality of transplanted watermelon. Proceedings of the Caribbean Food Crops Society 49:467-475. (Abstr.).

2012

Growth and Yield Response of Eight Hot Pepper Varieties in the U.S. Virgin Islands.

Hot peppers (Capsicum chinense) are important cash crop for small scale producers in the U.S. Virgin Islands and are grown mainly for fresh market. Challenges in hot pepper productions are high cost of labor and management, limited water resources, weeds, diseases and pests, limited land and natural disasters. The study of Nandwani and Forbes (2012) was conducted at the horticultural field plots of the UVI-AES. The objective was to conduct field evaluations of hot pepper varieties that are suitable to grow in the local soil and climatic conditions of the islands. Eight varieties, ‘Ring of Fire’, ‘White King’, ‘Compadre’, ‘Camino Real’, ‘Jalapeno M’, ‘Caribbean Red’, ‘Hungarian Yellow Hot Wax’, and ‘Aguila Real’ were tested in the field. Varieties selected with the cayenne (long and thin) type, bell shape fruits as well as round and wrinkled used as seasoning peppers. Transplants of all eight varieties were planted on 10 Oct. 2011 into rows 120 cm apart. Spacing was 60 cm within row. The trial was laid out by using a randomized complete block design with three replications and fields were irrigated with drip irrigation. Six harvests were conducted during the crop cycle. Data were collected on plant growth, tolerance to insect pests and diseases, marketable fruits, fruit weight, and marketable yield. Fruits were graded by size and condition as per U.S. Department of Agriculture’s grading system. Results of Scoville heat unit test (pungency) showed that ‘Caribbean Red’ is the hottest pepper among all the eight varieties tested. ‘White King’ was mildest pepper. No serious pests and diseases were observed in the crop. All eight varieties did set fruits during the season and were rated good or excellent in disease tolerance, yield, taste, and adaptability. Frequent rainfall during the late growing and harvest period affected quality production at some extent.

How to cite this study: Nandwani, D. and V. Forbes. 2012. Growth and Yield Response of Eight Hot Pepper Varieties in the U.S. Virgin Islands. Hortscience 47(9): S303 (Abstr.).

Weed Control in Okra [Abelmoschus esculentus (L). Moench] in the U.S. Virgin Islands.

Okra (Abelmoschus esculentus) is a highly valued vegetable and grown for fresh market in the U.S. Virgin Islands. Weed competition is an important factor affecting vegetable production. A study was conducted to evaluate preemergence application of two herbicides Preen Plus (Trifluralin) and Scythe (pelargonic acid) on weed control in okra. Two cultivars of okra, ‘Clemsen Spineless’, and ‘Red Burgundy’, were grown in conventional management system at the UVI-AES by Nandwani (2012b). The experimental design was complete randomized block and three replication (treated) and a control (weedy) for each cultivar. Preen Plus applied at a rate of (56.7 g/m, granular) a day prior to transplanting okra plants into the field and Scythe sprayed at the rate of 5% volume with water. No emergence of weeds was observed in treated plots within the first 2 to 3 weeks after application. Plants recovered from initial injury a few weeks after transplanting. Marketable yields were higher in ‘Clemsen Spineless’ (11,897 kg/ha) and ‘Red Burgundy’ (14,169 kg/ha) plots sprayed with Preen Plus in than in plots sprayed with Scythe where lower yield in ‘Clemsen Spineless’ (11,860 kg/ha) and ‘Red Burgundy’ (10,275 kg/ha) recorded.

How to cite this study: Nandwani, D. 2012b. Weed Control in Okra [Abelmoschus esculentus (L). Moench] in the U.S. Virgin Islands. Hortscience 48(9): S272-273 (Abstr.).

Growth and yield response of sweet pepper cultivars in the U.S. Virgin Islands.

Sweet pepper (Capsicum annuum) is a major vegetable for producers in the U.S. Virgin Islands and is grown for fresh market. Challenges in sweet pepper production are high cost of labor and management, limited water resources, weeds, diseases and pests, limited land and natural disasters. This study was conducted at the horticultural field plots of the UVI-AES in growing seasons of 2011-2012. The objective of Nandwani (2012a) research was to conduct field evaluations of sweet pepper cultivars that are suitable to grow in the local soil and climate of the islands. Thirteen cultivars, ‘Aristotle’, ‘California Wonder’, ‘Declaration’, ‘Dulce’, ‘Intruder’, ‘Jupiter’, ‘Mecate’, ‘Naples’, ‘Sweet Cherry’, ‘Sweet Banana’, ‘Sweet Savannah’, ‘White King’, and ‘Vanguard’ were tested in the field. Cultivars selected with the traditional lobe or bell shape fruits as well as longer, pointed shape known as banana peppers. Specialty colored peppers, orange, yellow and red were also tested. Transplants of all the pepper cultivars were planted into rows four feet apart. Spacing in plants was one foot within the row. The trial was laid out by using a randomized complete block design with three replications. ‘White King’ was the early maturity cultivar (65 days) and produced the highest total marketable yield (947 g/plant). ‘Aristotle’ produced biggest fruit (164.4 g/plant). ‘Intruder’ fruits were smallest (31.2 g/plant) and maturity of 76 days. ‘Sweet Cherry’ produced smallest fruit (13.6 g/plant) and lowest yield (246.6 g/plant) expected from the cherry type. Fruits were graded by size and condition. No serious pests and diseases were observed in the crop. All thirteen cultivars set fruits during the season and were rated good or excellent in disease tolerance, yield, taste and adaptability. Frequent rainfall during the growing period affected quality production at some extent. This paper presents results on plant growth, marketable yield, marketable fruit weight and maturity of thirteen cultivars of sweet pepper.

How to cite this study: Nandwani, D. 2012a. Growth and yield response of sweet pepper cultivars in the U.S. Virgin Islands. Proceedings of the Caribbean Food Crops Society 48:231-237. (Abstr.).