CAMPBELL, POPENOE AND OZAKI: TROPICAL FRUITS 361 ADAPTATION TRIALS OF TROPICAL AND SUBTROPICAL FRUITS ON SANDY SOILS IN BROWARD COUNTY, FLORIDA C. W. Campbell,1 J. Popenoe,2 and H. Y. Ozaki3 established before the dry season began. Plants were irrigated at the time of planting, but not Since the establishment of the Sub-Tropical thereafter. Many young plants which made little Experiment Station in 1930, there has been a growth during the first season after planting died continuous program of testing of tropical and from the effects of drought during the following subtropical fruits for adaptation to culture in winter. South Florida. Most of the testing has been done These trials included 3-tree plots of 61 species in the limestone soils of the Rockdale series in of tropical and subtropical fruit. All were planted Dade County. In 1953, R. B. Ledin and J. L. between 1953 and 1955, with the exception of 7 Malcolm, of the Sub-Tropical Experiment Station, species which were planted in 1956, and 4 species established a planting of tropical and subtropical which were planted in 1957. Regular observations fruits at the Plantation Field Laboratory, Fort have been made on growth, flowering, and Lauderdale, for the purpose of testing various fruiting. fruit introductions for adaptation to the soils of Thirty-five species have survived to the pres that area. This planting has been supervised and ent time, have grown well and fruited consist maintained until the present time by personnel of ently, and are obviously well adapted to culture the Sub-Tropical Experiment Station and the at the Plantation Field Laboratory. These in Plantation Field Laboratory. clude : The soil in this area is designated as Pompa- Achras sapota no and Delray fine sand. The trees were planted Antidesma dallachyanun in two-row beds with drainage ditches between Artocarpus hypargyraea (planted 1956) the beds. During much of the year, the water Artocarpus integra (planted 1956) table is maintained less than 24 inches below Butia capitata the surface of the soil. Carissa carandas In the establishment and maintenance of the Diospyros discolor planting, an effort was made to eliminate as many Dovyalis hebecarpa variables as possible, so that all species would re Dovyalis "hybrid" (abyssinica x hebecarpa) ceive the same treatment. Uniform fertilizer ap plications were made yearly. No minor element Table 1. Species which have survived up to 1962 at Plantation Field applications were made. The plot was mowed Laboratory, but have failed to thrive. several times a year, and grass and weeds were hoed away from the plants once or twice a year. Year Species Possible reasons for failure to thrive planted Frosts occurred several times, frequently causing the loss of young plants. The effects of frost Annona muricata 1954 Repeated cold injury were assumed to be nearly uniform over the plot. Annona reticulata 1955 Repeated cold injury The most variable factor has been the water Annona squamosa 1953 Repeated cold injury content of the soil. The water table was often Antidesma bunius 1955 Nutrient deficiency (perhaps zinc) high enough that a difference of a few inches in Blighia sapida 1953 Mechanical injury planting height made the difference between sur Carissa grandiflora 1955 Mechanical injury vival or death of small plants. This factor was Casimiroa edulis 1955 Not apparenc much less important in the case of well-estab Chrysophyllum cainito 1953 Repeated cold injury lished plants with extensive root systems. All Clausena lansium 1953 Nutrient deficiency plants were set in the soil as early in the rainy Dovyalis caffra 1957 Not apparent season as possible, so that they might be well Flacourtia cataphracta 1957 Repeated cold injury lAssistant Horticulturist, Sub-Tropical Experiment Sta Garcinia livingstonei 1957 Not apparent tion, Homestead. Melicocca bijuga 1954 Repeated cold injury 2Associate Horticulturist, Sub-Tropical Experiment Sta tion, Homestead. 1953 Water injury 3. Assistant Horticulturist, Plantation Field Laboratory, Fort Lauderdale. 1954 Mechanical injury, water injury Florida Agricultural Experiment Stations Journal Series No. 1552. 362 FLORIDA STATE HORTICULTURAL SOCIETY, 1962 Table 2. Species which have failed to survive at the Plantation Field Laboratoryo Year Year Species Possible reason for death planted died Anacardium occidentale 1956 1957 Nutrient deficiency, cold injury Averrhoa bilimbi 1953 1954 Cold injury, drought injury Averrhoa bilimbi replant 1954 1955 Cold injury, drought injury Averrhoa carambola 1954 1956 Cold injury, nutrient deficiency Canarium ovatum 1955 1956 Cold injury Coffea arabica 1956 1958 Cold injury Diospyros ebenaster 1954 1957 Water injury, cold injury Dovyalis abyssinica 1954 1956 Nutrient deficiency Flacourtia inermis 1957 1958 Gold injury Pouteria caimito 1955 1956 Cold injury Prunus persica 1953 1954 Rootknot nematode injury Prunus persica replant 1955 1956 Rootknot nematode injury Rubus alfeescens 1953 1954 Water injury Rubus albescens replant 1954 1955 Water injury Eleagnus philippensis (planted 1956) Pouteria campechiana Eriobotrya japonica Psidium cattleianum Eugenia aggregata Psidium guajava Eugenia dombeyi Rhodomyrtus tomentosa Eugenia jambos Spondias cytherea (planted 1956) Eugenia luschnathiana Syzigium cumini Eugenia unin'ora Tamarindus indica Euphoria longana Zizyphus mauritiana Feijoa sellowiana Fifteen species have survived to the present Flacourtia indica time, but have not flourished. These are listed Litchi chinensis in Table 1, with possible reasons for their fail Macadamia ternifolia ure to thrive. It should be emphasized that some Malpighia glabra of the species did not grow well because of me Mangif era indica chanical injury. Without further evidence, it Muntingia calabura obviously cannot be concluded that these species Myrciaria cauliflora are not well adapted to culture in sandy soils. Myrica rubra Eleven species have not survived to the present Phyllanthus emblica (planted 1956) time. They are listed in Table 2, with possible RUEHLE AND CONOVER: AVOCADO SCAB 363 reasons for their death. Death was often caused and other research organizations on the perform by a combination of factors. ance of these species in South Florida. It may be concluded that the adaptation plant ing has accomplished its purpose by demonstrat Summary ing that many uncommon tropical and subtropi In 1953, a planting of tropical and subtropical cal fruits will grow well in the sandy soils in the fruits was established at Plantation Field Labora area of the Plantation Field Laboratory with a tory, Fort Lauderdale, for the purpose of testing minimum of care and protection from low tem their adaptation to the sandy soils of that area. peratures. Many of the species which have died Sixty-one species were included in the planting. or failed to thrive can undoubtedly be made to Thirty-five species have survived to the present grow well in this area if careful attention is time (1962) and are obviously well adapted to paid to cold protection, fertilization, and soil culture in the area. Fifteen species have sur moisture. These observations are offered as an vived, but have not grown well, and 11 species addition to the data that have been collected over have not survived. Possible reasons for this the years by private individuals, nurserymen, are presented. FERBAM AS A CONTROL FOR AVOCADO SCAB George D. Ruehle and Robert A. Conover* trol of scab but failed to control Cercospora spot and anthracnose. Glyodin and Niacide also failed Vice-Director in Charge and Plant Pathologist to control these diseases. Phaltan caused mild Sub-Tropical Experiment Station injury to tender leaves in the March application. In 1960 excellent scab control was obtained with Homestead Tribasic copper and captan, but two experimental liquid copper formulations were phytotoxic. Oil Many avocado varieties, including Lula, the emulsion was less effective than copper for con leading commercial variety in Florida, are very trol of Cercospora spot. susceptible to avocado scab (Sphaceloma perseae Ferbam, diodine, captan, and a combination Jenkins) as well as to Cercospora (Cercospora of dodine and captan were compared with Tri purpurea Cke.) and anthracnose (Colletotrichum basic copper sulfate for control of avocado scab gloeosporioides Penz.) infections on fruits. It is in 1961. The test was conducted on Lula avo necessary to apply copper fungicides five to six cados. A single plot consisted of four trees, and times a year to secure clean fruit on highly sus there were three replications of each treatment. ceptible varieties. The first three of these appli Applications were made February 27, April 3, cations are made primarily for control of avo and May 9-11. Fruits were picked when mature cado scab. and classified as being scab-free, or having mild This fungicidal program is resulting in a or severe scab. Severe scab was defined as the gradual build-up of copper residues in the soil, amount of scab which would cause a reduction which eventually may reach levels toxic to the in fruit grade. avocado tree. Experiments were started in 1958 The results of this test, which are sum to find a substitute for copper. In the tests that marized in Table 1, show that copper and ferbam year, Dyrene and Thioneb failed to effectively were equally effective in controlling avocado scab. control scab. Phaltan and Thiram were promising Captan, dodine and the combination of the two for scab control but did not control Cercospora were less effective. Dodine was phytotoxic to the spot. Actidione