Effect of Greening on Fruit Size and Yield

Transcription

1 Effect of Greening on Fruit Size and Yield Tim Spann Chris Oswalt, Arnold Schumann & Michelle Danyluk International Citrus & Beverage Conference September 17, 2009 Clearwater Beach, FL

2 Introduction Greening causes fruit to be small, misshapen, lopsided, develop an off flavor and abscise prematurely Groves can become unproductive in as little as 2-4 years (Ke et al. 1988) Yield can be reduced by 10 to 80% depending on percent of canopy affected (Bassanezi et al. 2006) Need data for Florida

3 Objective Determine how greening infection alters fruit size, yield and quality characteristics to provide growers, processors, and packers with data to make better management decisions regarding harvesting, processing and packing fruit from infected trees/groves.

4 Experimental Sites 2007/08 9-year-old Valencia on Carrizo First HLB trees identified Dec Jan. 2008, 74 trees with visible symptoms, 6 PCR + Fruit harvested in April /09 Hamlin & Valencia near Felda Harvested Dec 2008, April 2009 Canopies ~40% symptomatic Hamlin, ~30% Valencia Hamlin near Lorida Harvested Feb 2009 Canopies ~20% symtomatic Valencia near Arcadia Harvetsed May 2009 Canopies ~30% symptomatic PCR+???

5 Lorida Hamlin trees: Healthy and HLB + Felda Hamlin trees: Healthy and HLB+

6 Methods 2007/08 Trees hand harvested April 9-11, healthy (symptomless) trees 6 HLB infected trees (PCR+) Fruit sized by hand based on fresh fruit size standards <125, 125, 100, 80, and 64s Fresh weight by size and total FW were recorded 125-size fruit were sorted into symptomatic and asymptomatic

7 Results 2007/08 Close to 50% of total yield was 125 or smaller fruit on infected trees compared to healthy trees HLB reduced total yield by ~25% (1 box) HLB trees were smaller so how much loss was due to canopy size? 125-size fruit on infected trees were 35% symptomatic

8 Methods 2008/09 10 HLB and 10 healthy trees harvested at each site Fruit sized (avg diam) and counted in the field on an Autoline fruit sizer OR sized, counted and weighed at the CREC Pilot Plant 1 sack (1-bushel) of small fruit and 1 sack of average fruit sampled from each tree Brix, acid, ratio and color Yield (weight) per tree estimated based on fruit size to weight relationship Measured tree height and two canopy widths to calculate canopy volume

9 Results 2008/09 Felda Hamlin

10 Results 2008/09 Felda Hamlin

11 Results 2008/09 Lorida Hamlin

12 Results 2008/09 Lorida Hamlin

13 Results 2008/09 Felda Valencia

14 Results 2008/09 Arcadia Valencia

15 What do these changes really look like?

16 Healthy 63% 25% Greening Felda Valencia fruit

17 Effect of Canopy Volume Greening infected trees were consistently smaller than healthy trees Felda canopy volume 44.5 m 3 vs m 3 Lorida canopy volume m 3 vs m 3 When yield is corrected for the canopy volume differences, infected and healthy trees are similar Felda yields lbs/m 3 vs lbs/m 3 Lorida yields lbs/m 3 vs lbs/m 3

18 Quality Results 2008/09 Hamlin HLB Healthy HLB Healthy Felda Brix Acid Ratio Color Juice Yield (ml/fruit) Small 9.25 c 0.95 a 9.87 b c d Average a 0.70 b a b b Small b 0.67 bc a a c Average 9.58 c 0.64 c a a a Lorida Small 8.16 c 0.80 a b b c Average 9.62 ab 0.66 b a a a Small a 0.68 b a a b Average 9.27 b 0.59 b a a a

19 Significance to Processors/Packers The vast majority of symptomatic HLB fruit are 63 mm (2.5 ) Felda (H) Lorida (H) Felda (V) Arcadia (V) HLB 47.7% 22.1% 11.8% 8.7% Healthy 11.4% 4.2% 1.9% 0.4% Eliminating symptomatic fruit may also eliminate up to 10% of healthy fruit that happen to be small Due to smaller fruit size total juice volume produced will be less from greening trees Is juice yield / lb of fruit different?

20 Significance to Processors/Packers Quality changes appear to be restricted to small, symptomatic fruit Potential off-flavors in greening fruit can be eliminated by grading For fresh fruit greening fruit will probably be handled by normal grading % loss will depend on severity of infection in the grove

21 Conclusions Data can be used to develop better economic models to determine best grove / processing / packing management strategies Costs of eliminations At what percent infection is it no longer cost effective to pick and process/pack Processors and packers should be able to eliminate most symptomatic fruit from the processing/packing stream to maintain product quality

22 Thank You