Cantaloupe is included in the melon group Cucumis melo cantalupensis in the Cucurbitaceae family. Cantaloupes are a relatively minor crop in Florida so there are no data available on commercial acreage, yield, production or value. However, there was a great increase in spring 2000 production in west-central Florida indicating the potential for a strong commercial cantaloupe industry in Florida.

The principal restraint on expansion of the cantaloupe industry in Florida has been the lack of dependable, high quality varieties. The ideal shipping variety for Florida should combine the following traits: 1) capacity to produce high yields; 2) fruit that is sutureless or nearly so, round to slightly oval, fully netted, a minimum 3 lb. weight with a thick, deep salmon interior, a small, tight seed cavity, and high soluble solids; 3) a pleasant aroma and taste; and 4) resistance to fruit rots and foliar diseases, especially downy and powdery mildew. Despite the absence of an intensive private and public breeding effort specifically for Florida, some material approaches these qualities. The object of this trial was to further evaluate outstanding varieties from the 1999 trial to identify non-sutured or slightly sutured, heavily netted cantaloupe varieties for potential production in west central Florida.

The EauGallie fine sand was prepared in early March by incorporation of 0-0.8-0 lb. N-P₂0₅-K₂0 per 100 linear bed feet (lbf). Beds were formed and fumigated with methylbromide:chloropicrin, 67:33 at 2.3 lb/100 lbf. Banded fertilizer was applied in shallow grooves on the bed shoulders at 2.52-0-3.50 lb N-P₂0₅-K₂0/100 lbf after the beds were pressed and before the black polyethylene mulch was applied. The final beds were 32-in. wide and 8-in. high, and were spaced on 5-ft centers with six beds between seepage irrigation/drainage ditches which were on 41-ft centers.

Eleven cantaloupe hybrids were direct seeded on 21 March in holes that were punched 2 ft apart in the black polyethylene mulch. The 20-ft long plots contained 10 plants each and were replicated four times in a randomized, complete block design. Weed control in row middles was by cultivation and application of paraquat. Pesticides were applied as needed for control of silverleaf whitefly (endosulfan and imidacloprid), downy mildew (chlorothalonil and azoxystrobin), and lepidopteris larvae (Bacillus thuringiensis, spinosad, and methomyl). Plant stand counts recorded just before the vines grew together showed that the stand of ‘Market Dream’ was only 70% and significantly lower than other entries despite reseeding.

Cantaloupes were harvested seven times beginning on 5 June and ending on 19 June. Marketable fruit were separated from culls that included fruit weighing less than 2.0 lb or that were cracked, rotted, or poorly shaped. Observations were made on fruit shape, sutures, and netting. Soluble solids were determined with a hand-held digital refractometer on several fruit from each entry on several harvest dates.

Early yields as represented by the first two of seven harvests ranged from 36 cwt/acre for ‘Market Dream’ to 367 cwt/acre for ‘Athena’. ‘Eclipse’ early yields was 364 cwt/acre. Average fruit weight of early-harvested cantaloupes varied from 3.5 pounds for ‘Sweet America’ to 8.6 pounds for ‘Minerva’.

Total marketable yields for the entire season varied from 265 cwt/acre for ‘Market Dream’ to 681 cwt/acre for ‘Minerva’. Three other entries had yields similar to those of ‘Minerva’. Average fruit weight ranged from 3.6 pounds for ‘Sweet America’ to 8.3 pounds for ‘Minerva’ which was statistically superior to all other entries. Soluble solids varied from 10.0% for HMX 7608 to 12.5% for ‘Vienna’. Very good internal quality is used to describe cantaloupes containing not less than 11% soluble solids. Using this criterion, only HMX 7608 would fail to qualify for very good internal quality. Cull fruit was between 56 cwt/acre for ‘Eclipse’ and 237 cwt/acre for ‘Market Dream’, despite having a reduced plant stand. The principal causes of cull fruit were stem-end cracks, fruit rots, misshapen fruit and undersized fruit. Marketable fruit per plant varied from 1.7 for ‘Vienna’ to 3.5 for ‘Sweet America’, but there was no significant difference among the entries.

Cantaloupe variety evaluation was conducted at this location in the spring 1999 season. Previous trials were in the spring 1988, 1990, and 1991 seasons. Total marketable yields from commercial hybrids in 2000 varied from 265 cwt/acre to 681 cwt/acre; in 1999 they ranged from 382 cwt/acre to 660 cwt/acre; in 1991 yields varied from 327 cwt/acre to 547 cwt/acre; in 1990 yields of commercial hybrids ranged from 300 to 566 cwt/acre. Accordingly, yields in 1999 and 2000 appear to be about 100 cwt/acre greater than those obtained almost a decade ago. Also, some of the more recently introduced hybrids are more dependable producers and have better shipping qualities than those previously available.

Tomato Spotted Wilt Virus (TSWV) was first documented in the north Florida/ south Georgia production area in 1986. In the beginning the virus was at a low level with periodic outbreaks in the fall. In the past few years it has become a serious problem in the spring crop, with incidence ranging from as little as 10 % to almost 100 %. Most losses from TSWV are due to primary infection, which past research has shown that primary infection can not be prevented with insecticide sprays. Secondary infection within a field can however be reduced by insecticide applications. The primary vector in the spring has been the Western Flower Thrips (WFT). At this time the lack of reliable management tactics stands as a major impediment to the implementation of integrated pest management in tomatoes in the southeastern United States.

For the past 5 years experiments have been conducted at the North Florida Research and Education Center (NFREC), Quincy to investigate tactics that can reduce WFT numbers and incidence of TSWV. Potential management strategies would include those which prevent or slow the initial movement of thrips onto plants in the tomato fields, which would reduce the primary spread of TSWV. One such tactic which is showing a great deal of promise is use of highly reflective (metalized) mulches. These metalized mulches have a thin layer of aluminum applied to a polyethylene mulch and usually have reflectance levels of 75 % or higher.

Insect and Disease Control: In replicated spring trials from 1996 through 2000, metalized mulches have consistently reduced WFT numbers by up to 50 % in tomato flowers. When the number of thrips is reduced, the primary spread of TSWV is also reduced. For example, in 1997, nearly 40 % of plants grown on black mulch were infected, while only about 20 to 25 % of plants grown on metalized mulch plots were infected with TSWV at harvest time.

Large scale grower trials have also been evaluated. In early April of 1998 approximately 1 acre of a 15 acre tomato field had metalized mulch applied. Early growth was slower than the black mulch due the cooling effect of the metalized mulch. As temperatures increased the growers remarked that the plants on the metalized beds caught up with the plants on the black mulch and by the end of the season the plants on the metalized beds were larger than those on the black mulch. The 1 acre block was scouted separately from the rest of the field. By harvest time the incidence of TSWV was only 10 % in the metalized area compared to 19 % in the black mulch area. In the spring of 2000 these same growers had a field of 30 acres where they used the metalized mulch for tomato production. At final scouting date (6/18/00), the metalized field had an incidence of 11 % compared to 45 % in the black mulched area, a 75 % reduction in virus.

Yields: The metalized mulch was also evaluated for its effect on tomato yield and fruit size. In the spring of 1998, with ‘FL 47' tomatoes, the black mulch produced significantly higher yield on a per plant basis than those on the metalized mulch beds (Table 1). However, on a per acre basis there were no differences in yields between the two mulch systems. One reason for this is that the metalized mulches are much cooler than the black mulch due to the reflection of sunlight back up away from the beds. Early season growth on the metalized mulch is mulch slower, thus the reduction in yield on a per plant basis. Early season soil temperatures have been more than ten degrees cooler under the metalized mulch than the black mulch. However, the overall yields with the metalized mulch were equal to those produced on the black mulch due to the reduction of TSWV with the metalized mulch. Fruit size was not affected by mulch type. Because of this cooling effect on soils we do not recommend use of metalized mulches for late February or early March planting in the north Florida/ south Georgia production area.

In the fall of 1998, production on metalized mulch was compared to production on white on black mulch which is standard for fall (mid July to mid August) planting. From earlier trials the metalized films were found to have even greater cooling effects on beds than the white on black. Neither yields or fruit size of ‘Equinox’ tomatoes were affected by mulch type (Table 2).

In the spring of 1999, from a late March planting, neither yields or fruit size were affected by mulch type (Table 3). Early production season of 1999 was warmer than 1998 negating early growth differences. Also incidence of TSWV was not affected by mulch type, probably due to plot to plot interference of mulch type. In our experiments we have found the presence of the metalized mulch can have an affect on plots as far away as 18 feet and can confound small plot trials.

Summary: The use of metalized mulches in tomato production for suppression of WFT numbers and incidence of TSWV has shown great promise. Our research has shown that use of the metalized mulch can result in a reduction in TSWV even greater than currently labeled insecticides when compared to unsprayed controls. Costs of the metalized mulch are about 25 % higher than that of other mulches currently used in tomato production, but large scale field trials have shown that the extra costs are justified due to the suppression of TSWV. At this time we do not recommend their use for early spring plantings due to their cooling effect on the beds. In some grower trials, we have looked at using metalized strips in the drive rows during early plantings and have shown reduction in TSWV in the rows next to the metalized strip. We also plan to evaluate painting a narrow strip black down the middle of the metalized beds to look at the effect on early plantings for yields and thrips and TSWV control. The metalized mulches are hard for the field crews to work around due to their blinding effect and growers have had to provide sunglasses to their field help. 

The value of fresh market green bell peppers was $243 million for the 1998-99 season (Fla. Agric. Stat. Serv., 2000). During that season 21.6 million bushels (28-lbs) were harvested from 19,000 acres for an average yield of 1,138 bushels per acre. The average price per bushel was $11.24. Pepper production is concentrated in South Florida with 25% (4,700 acres) being produced in Eastern Palm Beach County. Bacterial leaf spot, caused by Xanthomonas compestris pv.vesicatoria, is one of the most widespread and serious diseases affecting production of pepper in Florida (Pohronezny et al., 1993 and Pernezny et al., 1998). Pepper varieties with resistance to races 1, 2, and 3 of the pathogen have been commercially available for several years and seed companies continue to develop new cultivars with resistance to this disease (Shuler, 1993, 1995, 1996, 1997, 1998, 1999, and Shuler et al., 2000).

Experimental Design: Forty-three varieties were replicated in a complete block with four replications for the evaluation of green fruit. All of the varieties were resistant to bacterial spot races 1, 2, and 3 except PR 93-2-1 (resistant to race 2 only) and Paladin (no resistance). The demonstration was in a commercial planting managed by Thomas Produce, Inc. and located at Bob West Rd., and US 441, Delray Beach, FL. The soil type was a Myakka sand.

Plots were single beds spaced 5.0 feet on center and 9.0 feet long with two rows of plants spaced 18 inches apart. Within-row plant spacing was 9 inches (12 plants per row or 24 plants per plot, 23,232 plants per acre).

Crop Culture and Evaluation: Transplants were grown by LaBelle Plant World in flats (228 cell) and were seeded September 9. Plants were 47 days old when transplanted on October 26, 1999. Plants were set on raised beds with white on white polyethylene plastic mulch. The beds had been fumigated with methyl bromide/chloropicrin 67/33. Severely weakened and dying plants were counted on October 28 and November 4 and 10 and replaced with original transplants. Plots were also evaluated for either dead or weakened plants on November 18 and at each harvest, but these plants were not reset. The plants were relatively small and were not tied.

Green peppers were picked three times: January 26, February 16, and March 9. At each harvest marketable fruit were counted and weighed. At first pick ten pepper each from two blocks were randomly selected and measured for length and width, number of lobes, and pointed and blunted fruit were counted. Colored fruit (red or yellow) from a separate block were picked four times: February 8, 17, 29, and March10 and evaluated for softness, sunburn, flat and misshapen, soft rot, stip, and for being completely colored with no green showing. Incidence of bacterial leaf spot was relatively low for most varieties; varieties were rated for the disease on January 27 (one day after first pick).

Weather and Crop Conditions: Weather was considered moderately favorable for crop growth. On October 15, after the beds were made, Hurricane Irene passed by bringing strong winds and heavy rainfall with temporary flooding which may have leached out some of the preplant fertilizer. Two weeks after transplanting, leaves of some plants had a light yellow caste and the plants seemed to stop growing. After three weeks the yellowing seemed to be confined mostly to the lower, older leaves. This yellowing/stunted response seemed to be associated with specific plant rows since by the third week most of the plants had darker green foliage and had resumed growth.

Results and Discussion: Varieties are listed in order of total yield for green fruit, Table 1. For most of the columns of data, values for the top ten varieties are in bold face. Desirable characteristics for pepper include high yields, large fruit (low numbers of fruit/carton), ratio of length to width near 1.00 (blocky), a high percentage of 3 and 4 lobed fruit with the average number of lobes near 4.0, and a low percentage of blunt or pointed fruit. Fruit characteristics (length and width, number of lobes, and blunt or pointed fruit) were only evaluated for the first pick when fruit size is usually the largest. A low rating in any one of these areas could be a reason for not growing a variety.

Green Fruit There were relatively small differences in yield between varieties with a range of 107 cartons/A for the top five varieties, a range of 74 cartons/A for varieties ranked 6-10, and a range of 54 cartons/A for varieties ranked 11-15. Four of the top ten yielding varieties were also among the top ten in fruit size (Enza 31702, Lafayette (5044, yellow), Rogers 6088, and PR 93-2-1). All of these four were considered blocky to slightly elongated except Lafayette which was slightly flattened (length to width ratio 0.94). Each of these four had 100% 3 & 4 lobed fruit except Rogers 6088 which had 90%. Five of the top 10 yielding varieties were considered very blocky (length to width ratio 0.95 to 1.10): Orion, Crusader, Rogers 6088, PR 93-2-1, and ACX 217. There were 11 varieties which had no blunt or pointed fruit at the blossom end; only one of these varieties, Sentry, was among the top10 in yield. Three of the top 10 yielding varieties had only 5% blunt or pointed fruit at the blossom end.

Colored Fruit Fruit which were picked were considered to be in some stage of color development on approximately 67% of their surface. It is not known how quickly or completely these fruit would have turned to full color.

In the Fall 1998 demonstration, a grower selected four varieties at first pick as being especially desirable for red fruit [Sakata 6112, Crusader (6110), Legionnaire (6089), and Lexington]. In the Fall 1999 demonstration, the primary cause for culls was fruit with soft or wrinkled sides. This may indicate that fruit were over mature when picked. If fruit had been picked earlier there would have probably have been less loss to this problem. Stip was only found in five of the 43 varieties (Paladin, X3R Camelot, X3R Wizard, Sakata 7118, and Rogers 6088). Paladin had the largest number of fruits with stip with 23.2%. The severity of stip was very light to light and it was judged that many of the fruit would have been marketable.

Literature Cited

Florida Agricultural Statistics Service. 2000. Vegetable summary 1998-99. Florida Agric. Stat. Serv., Orlando, FL.

Pohronezny, K., R. E. Stall, S. Subramanya, and K. D.Shuler. 1993. Integrated control of bacterial spot on peppers. Florida Grower and Rancher. 86(6):8.

Pernezny, Ken, Robert Stall, Ken Shuler, Janice Collins, and Myrene Hewitt. 1998. Results of a survey of bacterial spot races (Xanthomonas campestris pv. vesicatoria) in pepper in South Florida, spring 1998. Palm Beach County Extension Report (PBCER) 1998-9.

Shuler, K. D. 1993. Performance of bell pepper varieties with resistance to bacterial spot, DuBois Growers, Boynton Beach, FL, fall/winter 1993. PBCER 1994-1.

Shuler, K. D. 1993. Effect of different within-row plant spacings and tying on bell pepper yield, DuBois Growers, Boynton Beach, FL, fall/winter 1993. PBCER 1994-3.

Shuler, K. D. 1995. Performance of bell pepper varieties with resistance to bacterial spot, DuBois Farms, Boynton Beach, FL, fall/winter 1994. PBCER 1995-2.

Shuler, K. D. 1996. Performance of bell pepper varieties, Thomas Produce, Boca Raton, FL, winter/spring 1995-96. PBCER 1996-6.

Shuler, K. D. 1997. Performance of bell pepper varieties over seven sequential plantings in Southeast Florida, 1996-97. Proc. Fla. State Hort. Soc. 110: 287-294.

Shuler, K. D. 1998. Performance of bell pepper varieties, planting #2, Green Cay Farm, Boynton Beach, FL, fall 1997-98. PBCER 1998-2.

Shuler, K. D. 1998. Performance of bell pepper varieties, planting #3, Thomas Produce, One Mile Road Farm, Delray Beach, FL, fall/winter 1997-98. PBCER 1998-3.

Shuler, K. D. 1998. Performance of bell pepper varieties, planting #4, Bedner Farms, Bowman Land, Starkey Road, Delray Beach, FL, fall/winter 1997-98. PBCER 1998-4.

Shuler, K. D. 1999. Performance of bell pepper varieties, DuBois Farm, Delray Beach, FL, winter/spring 1998-99. PBCER 1999-2.

Shuler, K. D., K. L. Pernezny, and J. L. Collins. 2000. Performance of bell pepper varieties, Thomas Produce, Snake Farm, Delray Beach, FL, fall/winter 1999-2000. PBCER 2000-2.