Bitter melon (Momordica charantia), also known as bitter gourd, karela, or balsam pear (Palada and Chang, 2003), is a popular vegetable for many culture groups in Canadian urban centers, such as the Greater Toronto Area. Consumption of bitter melon has also been shown to be beneficial for the management of some symptoms of type II diabetes (Abascal and Yarnell, 2005). It is estimated that there is a CAD$12.4 million/year market for bitter melons in just a few of the largest Canadian metropolitan centers, and a potential countrywide market of CAD$37–66 million/year (Zheng, 2010).
Currently, the majority of bitter melons sold in Canada are imported from other countries such as Honduras (Zheng, 2010). However, for the imported bitter melons, the lost freshness due to a short postharvest life of the fruits (Palada and Chang, 2003) negatively affects their price, and Canadian consumers also worry about food safety of imported bitter melons. Moreover, there is hardly any organic bitter melon in Canadian market. Although there is a demand for local, organically produced bitter melon, the supply of such products is currently limited by Canada’s cold climate (Zheng, 2010). Bitter melons, which are native to southern China and eastern India, grow well in tropical and subtropical climates (Behera et al., 2010). In Canada, OF production of warm-season crops such as bitter melons is difficult unless some means are employed to improve the growing environment (Waterer, 2003).
HTs, as low-cost protective structures, can create a warmer microclimate for plants and have been used worldwide to promote earlier crop production, higher yields per unit area, and better-quality products compared with OF production (Lamont, 2009; Ogden and Van Iersel, 2009). However, since HTs are unheated and passively ventilated structures, the actual benefits of HT production for different crop species are determined by local environmental conditions (Carey et al., 2009). There is limited information on HT production under Canadian climatic conditions, especially in Ontario. In Saskatchewan, it has been reported that crops of muskmelon, pepper, and tomato in HTs matured 1 to 2 weeks earlier and produced substantially greater fruit yields before frost than those in low tunnels (Waterer, 2003). However, no information is available on whether HTs can be used for bitter melon production in regions with similarly short growing seasons, such as Ontario.
For organic production, the use of anti-insect netting on the vents and doors of HTs is often recommended, since it can provide a nonchemical way to effectively exclude many insect pests (Teitel, 2001). For bitter melon production in tropical and subtropical regions, the most common insect pests are fruit flies, beetles, thrips, aphids, and mites (Palada and Chang, 2003). These pests have been found in other cucurbit crops in southern Ontario. To exclude these pests, the maximum mesh size of anti-insect netting needs to be small; up to around 200 μm (Bethke and Paine, 1991). However, fine mesh size also impedes air flow through the netting and may thus increase temperature inside HTs (Fatnassi et al., 2006). During summer in southern Ontario, solar radiation intensity often exceeds most crops’ requirements (Llewellyn et al., 2013). Excessive solar radiation can increase air temperatures beyond the optimum for growing crops in protected agricultural structures that use passive ventilation, including HTs (Zhang, 2001). It is therefore important to test the impact anti-insect netting has on HT temperature and organic bitter melon production, including growth and harvest metrics as well as incidence of insects and diseases.
The objectives of this study were to explore the feasibility of organic production of bitter melons in HTs in southern Ontario, and to determine the effects of anti-insect netting on HT production of organic bitter melon.
Behera, T.K., Behera, S., Bharathi, L.K., John, K.J., Simon, P.W. & Staub, J.E. 2010 2 Bitter gourd: Botany, horticulture, breeding Hort. Rev. 37 101 141
Both, A.J., Reiss, E., Sudal, J.F., Holmstrom, K.E., Wyenandt, C.A., Kline, W.L. & Garrison, S.A. 2007 Evaluation of a manual energy curtain for tomato production in high tunnels HortTechnology 17 467 472
Canadian Food Inspection Agency 2009 Organic products regulations. Vol. SOR/2009-176, Minister of Justice
Carey, E.E., Jett, L., Lamont, W.J., Nennich, T.T., Orzolek, M.D. & Williams, K.A. 2009 Horticultural crop production in high tunnels in the United States: A snapshot HortTechnology 19 37 43
Díaz-Pérez, J.C., Muy-Rangel, M.D. & Mascorro, A.G. 2007 Fruit size and stage of ripeness affect postharvest water loss in bell pepper fruit (Capsicum annuum L.) J. Sci. Food Agr. 87 68 73
Fatnassi, H., Boulard, T., Poncet, C. & Chave, M. 2006 Optimisation of greenhouse insect screening with computational fluid dynamics Biosyst. Eng. 93 301 312
Islam, M.S., Mia, M.A.B., Das, M.R., Hossain, T., Ahmed, J.U. & Hossain, M.M. 2014 Sex phenology of bitter gourd (Momordica charantia L.) landraces and its relation to yield potential and fruit quality Pak. J. Agr. Sci. 51 651 658
Jett, L.W. 2006 High tunnel melon and watermelon production. Vol. 173. University of Missouri Extension
Lamont, W.J., Orzolek, M.D., Holcomb, E.J., Demchak, K., Burkhart, E., White, L. & Dye, B. 2003 Production system for horticultural crops grown in the Penn State high tunnel HortTechnology 13 358 362
Llewellyn, D., Zheng, Y. & Dixon, M. 2013 Survey of how hanging baskets influence the light environment at lower crop level in ornamental greenhouses in Ontario, Canada HortTechnology 23 823 829
Lubitz, W.D., Zheng, Y., Kong, Y. & Llewellyn, D. 2016 A field study of the microclimate within high tunnel greenhouses. Proc. Canadian Society for Mechanical Engineering International Congress 2016, Kelowna, British Columbia, Canada
Ma, Q., Chen, Y., Qu, J., Dai, X. & Yin, T. 2013 Modeling and analyzing the dynamic growth for progeny in a full-sib family of Salix xuzhouenesis J. Nanjing For. Univ. 37 13 16
Mohammed, M. & Wickham, L.D. 1993 Extension of bitter gourd (Momordica charantia L.) storage life through the use of reduced temperature and polyethylene wraps J. Food Qual. 16 371 382
Morgan, W. & Midmore, D. 2002 Bitter melon in Australia. A report for the Rural Industries Research and Development Corporation. RIRDC Publication No 02/134:36. <http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.31.31.511.8491&rep=rep8491&type=pdf>.
Ogden, A.B. & Van Iersel, M.W. 2009 Southern highbush blueberry production in high tunnels: Temperatures, development, yield, and fruit quality during the establishment years HortScience 44 1850 1856
Palada, M.C. & Chang, L.C. 2003 Suggested cultural practices for bitter gourd, AVRDC International Cooperators’ Guide. Vol. 03-547, AVRDC, pp. 5. <file:///C:/Documents%20and%20Settings/Administrator/My%20Documents/Downloads/bittergourd%20(22).pdf>.
Riederer, M. & Schreiber, L. 2001 Protecting against water loss: Analysis of the barrier properties of plant cuticles J. Expt. Bot. 52 2023 2032
Standards Council of Canada 2006 Organic Production Systems General Principles and Management Standards. Vol. CAN/CGSB-32.310-2006. Canadian General Standards Board
Wang, Q. 2003 Year-round cultivation of bitter melon with high yield. Scientific & Technological Documentation Publishing House, Beijing, China
Zhang, F.M. 2001 Protected horticultural science. China Agricultural Publishing House, Beijing, China
Zheng, Y. 2010 Are there sweet profits growing bitter melon. Canadian Greenhouse Conference, Toronto, Ontario, October 6–7