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Growth and Yield of Hurricane-damaged Tomato Plants

Introduction

Florida suffered the effects of four hurricanes during Fall 2004. Losses to agriculture occurred during a 7 week period, beginning with hurricane Charley on Aug. 13 and ending with Jeanne on Sept. 27. Many vegetable growers along Florida’s eastern coast replanted after the first two hurricanes but decided not to replant after the third. Even before the fourth hurricane arrived, it was estimated that more than two billion dollars were lost to Florida agriculture (DOACS Press Release, 24 Sep 2004).

Not all growers chose to replant or abandon their fields. Some in southwestern Florida chose to nurse their plantings back to health. This report documents injury, growth, and yield of hurricane-damaged tomato plants in large-scale commercial conditions.

Materials and Methods

Tomato seedlings, cultivar 'Florida 91', were grown 5 weeks in a commercial transplant production facility and then transplanted to raised beds at a commercial farm near Immokalee, Florida on 21 Aug. 2004. Beds were six-inches high, 34-inches wide, and covered with white-on-black plastic mulch. The soil is a Basinger fine sand (sandy, siliceous, hyperthermic, Spodic Psammaquents). Hurricanes Frances and Ivan occurred 15 and 24 days, respectively, after transplant, though hurricane Frances caused by far the greatest damage to plants discussed in this report. Plants were not staked and supported at the time of these hurricanes. Hurricane Charley arrived on Aug. 13 and occurred before transplant.

Plants were rated Sept. 24 and placed in one of four categories according to size and apparent vigor: best, good, fair, and poor (Fig. 1). Plants rated poor, which were small and stunted, were not further evaluated during this study because these plants were not expected to survive or produce any yield.

Soil located within 3 inches of the base of each stem was removed for analysis of soluble salts. Ten plants of each category were then removed from beds by hand with roots intact. In the lab, roots were washed by hand to remove soil and any potting media still remaining in the original transplant plug. Injury was most evident on sections of stem just below the soil surface. Plants were divided into three parts: (1) shoots, stems, and leaves, (2) roots located above stem injury, and (3) roots located below stem injury. All tissue was then dried in a forced-air, constant-temperature room at 54 ˚C for 7 d and dry mass recorded.

Three samples of each category were harvested from the field the same day as those described above and examined by the SWFREC Plant Pathology Lab for the presence of potential root or soil borne pathogens.

Ten additional plants of each category, located in the same area of the field as those described above, were not removed from the field but were labeled for future sampling. Fruit from each plant was harvested Nov. 8 and 22 and then separated by size into standard market grades. Each individual fruit was weighed. Commercial harvest of the field precluded a third harvest. The anova procedure of SAS v. 8.01 was used for all analyses (SAS Institute Inc., Cary, N.C.).

Results

Winds from hurricanes Charley, Frances, Jeanne and, to some extent, Ivan greatly affected vegetable plantings in southwest Florida, though the intensity and duration of each varied in the Immokalee area (Fig. 2). Figure 2 shows wind speed and direction at Immokalee, Florida during Aug. and Sept. 2004. Readings were recorded by an automated weather system (FAWN) every 15 minutes at a height of 33 ft (10 m). There were four named hurricanes during this period.

Tomato plants described in this report were injured by Frances with maximum winds in the Immokalee area of approximately 80 mph. Winds of Frances were more sustained and lasted longer than any of the other hurricanes. Winds from Frances originated from the north and slowly rotated to the west, south, and then southeast (Fig. 2).

Hurricane Ivan was half the intensity and duration of Frances and was not a serious threat in the Immokalee area. Winds from Jeanne entered the Immokalee area from the north on Sept. 27 and, like Frances, rotated to the east and south. Hurricane Jeanne was as intense as Frances, with winds in excess of 80 mph, but its duration was not as long as that of Frances.

Plants exposed to these winds exhibited varying amounts of stem damage. Stem damage occurred just below the soil line and appeared to be the result of plants being whipped around in the planting hole by strong winds.

Plants sampled 34 d after transplant and just 19 d after Frances and that were rated best exhibited significantly more shoot and root dry mass than plants rated good or fair (Table 1). Stems exhibited various amounts of scar and callous tissue where plants had been whipped around in the planting hole by hurricane-force winds. Roots of plants rated best were thick and fleshy and were located mostly below the area of the stem that was damaged (Fig. 3a). In contrast, rooting below the damaged area was severely affected in plants rated good and fair (Fig. 3b). Measurements of soil EC indicate that salt buildup at the base of the plants and around the planting holes did not contribute to this damage (Table 1).

Plants tested for the presence of common soil-borne pathogens had no evidence of Phytophthora spp. (Table 2). Recovery of Pythium spp. and Fusarium spp. was greater among plants rated fair compared with those rated best. Plants rated good were intermediate. Slightly greater recovery of bacteria occurred in plants rated best and good than in plants rated fair.

Plants injured by Frances and rated best produced significantly more early yield (first harvest) than plants rated good or fair (Table 3). Plants rated good produced 43% lower total early yield and 48% lower extra-large early yield than plants rated best. Plants rated fair produced 46% lower total early yield and 67% less extra-large early yield than plants rated good.

During the second harvest, plants rated good produced 110% higher extra-large yield than plants rated best. Total yields for the second harvest were not significantly different among any of the treatments.

Discussion

Upon reflection, it was a wise decision by these growers to nurse hurricane-damaged plants back to health rather than replant the field. Early yield from these plants occurred during a time when market prices were high, about $40 or more per 25-lb box, and these prices would not have been captured if the field had been replanted.

Growers were careful to adjust their normal water, fertilizer, and pest control programs in response to the needs of their damaged crop. First, they increased the moisture content of plant beds to ensure that roots arising from above the damaged areas of the plant stems, located at the surface of the plant bed, would not dry out. Second, they did not assume the plant could easily find nutrients already present in the plant bed, which were applied during preplant preparation of the field. Instead, they provided a complete nutrient mix through irrigation tubing. Third, they adjusted their spray program to minimize further damage caused by opportunistic pathogens invading fresh wounds and weakened plants.

The rating scale used in this research—best, good, and fair—was an arbitrary one. It cannot be known how these plants would perform compared to those not damaged by hurricane-force winds. Despite this limitation, it is clear that plants rated best produced greater early yields than plants rated fair, and plants rated best probably would have produced greater total yields if third harvest yield had been recorded. Yields of plants rated good and fair appeared to recover, but yields seemed be somewhat delayed compared to that of plants rated best.

In conclusion, tomato plants can sustain a surprising amount of wind injury and still recover, producing high yields when growing conditions are carefully managed. However, early yields were greatly affected by hurricane-force winds. Yields decreased as injury increased, especially in the extra-large size category. Finally, damage to plants was highly localized. Plants described in this report were mostly affected by Frances. Plants on the same farm and located less than a mile away were affected by Jeanne (Fig. 4). Plants shown in the foreground of Fig. 4 were later removed and the area replanted. Plants in the background were left intact and nursed back to health.

(Kent Cushman, assistant professor, SWFREC-Immokalee, Karen Armbrester, Gene McAvoy, Ronald French, and Pam Roberts, Vegetarian 05-01)