LIBRO-CONGRESO-CITRUS

S11O06
Reduction of fruit splitting and the incidence of creasing of ‘Nova’ mandarin and ‘Washington’
navel orange by NAA sprays
Greenberg J. 1 , Kaplan I. 1 , Tagari E. 1 , Fainzack M. 2 , Egozi Y. 2 , and Giladi B. 2
1 Ministry of Agriculture, Extension Service, Israel; and 2 Mehadrin-Prior, Israel. yogreen@shaham.moag.gov.il
‘Nova’ mandarin and ‘Washington’ navel orange in Israel suffer from peal splitting, causing fruit loss of up
to 50,% and from creasing, disqualifying the fruit for fresh marketing. The effects of naphthaleneacetic acid
(NAA 300mg/L), tank-mixed with ‘Bonus-NPK’ fertilizer (5%), on the yield, fruit number, fruit size, fruit quality,
fruit splitting and creasing were studied. In ‘Nova’ mandarin, different application times were examined, on
small fruitlets (15-20 mm in diameter)-when NAA causes fruit thinning, and on larger fruitlets (26-32 mm
in diameter) when NAA does not affect fruit abscission. NAA spray on large fruitlets reduced creasing from
37% in control to 10% in sprayed trees. Moreover, fruit drop due to splitting was also reduced by 14%. In
‘Washington’ navel orange, NAA spray on large fruitlets (30 mm) reduced creasing by 30%, while the common
spray with giberellic acid (20 mg/L) in August reduced creasing by 20%. In both varieties, NAA sprays on small
fruitlets reduced fruit number and yield, while spraying larger fruitlets had no effect on fruit number or yield.
The NAA sprays had no significant effects on the percent of juice, total soluble solids and the acid content of
the fruit. The data suggest that NAA treatment is effective in reducing creasing and splitting when sprayed
on large fruitlets, at the stage that it does not affect fruit size and fruitlet thinning anymore. Results and their
implication regarding cultural practices are discussed.
S11O07
On-farm citrus trials in Australia: Effective extension for commercial assessment
Falivene S. 1 , Connolly K. 1 , and Cannard M. 2
1 NSW Department of Primary Industries (NSW DPI), Intensive Industries, Australia; and 2 Murray Valley Citrus Board (MVCB), Australia.
steven.falivene@dpi.nsw.gov.au
Many products and practices have been promoted to the citrus industry and little is known about their
performance under Australian conditions. Some of these products have been trialed within Australia.
Performance of some of these products on farm has been highly variable causing confusion in the industry.
The variability is probably due to differences in site (e.g. soil, climate, variety) and management (e.g. irrigation,
nutrition). This project assesses the cost benefit of a number of citrus practices promoted to industry on
grower’s properties. The project utilizes active learning principles by facilitating grower participation with
trials (planning, maintenance & reporting). Over 20 trials have been implemented in the past two seasons.
Trials included ground and foliar potassium applications, pruning, foliar fruit size sprays, kaolin clay foliar
sprays and crop regulation. Trials have resulted in cost saving with reduced potassium application. The project
developed tools and methods to enable efficient and effective in-field collection and analysis of data. This
enabled the project to implement more trials. Single tree replicated trials (RCBD) are the favored method to
conduct trials. Grower feedback has been very positive indicating that it has helped them make improved
and cost effective management decisions. On-farm trials are a very effective extension method to obtain fast
assessment and adoption of best management practices suited to site conditions.
S11O08
Evolution of citrus mechanical harvesting in Florida – Lessons for the future
Roka F.M.
University of Florida (UF), Southwest Research and Education Center, USA. fmroka@ufl.edu
Florida citrus growers have invested more than $40 million since 1995 to develop mechanical harvesting
systems. Technological improvements allowed mechanically harvested acreage to increase steadily between
1999 and 2009 and reach more than 14,000 hectares. Since 2009, however, the trend for mechanical
harvesting has been downward and by the end of the 2010-11 season, the number of hectares mechanically
harvested had fallen by two-thirds. Reasons behind the movement away from mechanical equipment include
XII INTERNATIONAL CITRUS CONGRESS 2012 - 179
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