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CATTS is a system that controls temperature, atmosphere, and treatment time to effectively treat tree fruits for pests. It optimizes insect mortality and commodity quality using a combination of controlled atmosphere and heat treatments.
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Temperature Time CA Atmosphere CATTS Quarantine Treatments for Tree Fruits Lisa G. Neven USDA-ARS Yakima Agricultural Research Laboratory
Temperature Time CA Atmosphere Controlled Atmosphere Temperature Treatment System CATTS Controls & Monitors: O2, CO2, Air Speed, Humidity, Dew Point, Air Temperatures, Heat Rate, Fruit Temperatures (surface & core)
Temperature Time CA Atmosphere What CATTS Does • Oxygen is reduced to a level which will not support active metabolism in the insects. • High carbon dioxide levels prevents the insect from ‘down regulating’ metabolism and respiration. • High temperatures cause metabolic stress in the insect, and large scale systems break down occurs. • Combination CA & Heat causes mortality about 2X as fast as heat alone.
Zone of Opportunity Host Tolerances Pest Intolerances Illustration of the ‘zone of opportunity’ for optimization of insect mortality and commodity quality using a heat treatment.
Zone of Opportunity Pest Intolerances Host Tolerances Illustration of the ‘zone of opportunity’ for optimization of insect mortality and commodity quality using a CATTS treatment.
Considerations for CATTS Treatments • Fruit Physiology • Insect Physiology • CATTS Treatments • Engineering of Commercial Units
Fruit on the Tree • While fruit are on the tree, they experience fluctuating temperatures. • In response to these fluctuating temperatures, the fruit produce a number of ‘stress response’ proteins. • The fruit will produce these proteins even if the daily temperatures are not in the ‘stress’ range every day.
41.5°C August 12 41.3°C 42.0 37.0 32.0 Temperature °C 27.0 22.0 17.0 12.0 1:35 3:05 4:35 6:05 7:35 9:09 1:39 3:09 4:39 6:09 7:39 9:09 12:05 10:39 12:09 10:39 12:09 Time air deep shallow deep Apple Temperatures During a Typical Summers’ Day in Washington State
120 C1 100 C2 90 Temperature °F C3 80 70 C4 60 12:00:00 AM 12:00:00 AM 12:00:00 AM 12:00:00 AM 12:00:00 AM Time Peach Fruit Temperatures on the tree 110
Cherries on the Tree in Tasmania Cherry core temperatures in Tasmania, Australia where daily high air temperatures are below 30°C.
Fruit after Harvest • After harvest, the fruit will continue to make the ‘stress response’ proteins for a number of days. • These proteins will help the fruit tolerate heat treatments.
Fruit and CATTS • There is no evidence that the high carbon dioxide and low oxygen levels during CATTS causes any additional phytotoxicity. • This may be due to the high capacity for anaerobic metabolism in the fruit. • We do know that heating rate is very important for preventing damage. • We also know that heat disrupts many of the enzymes involved in ripening.
Insects in the Fruit • Insects in the fruit will also produce ‘stress response’ proteins when fruit temperatures reach ‘stressful’ levels. • Insects will only produce these proteins when they experience stressful temperatures. • When the fruit is harvested, and the insects are no longer exposed to stressful temperatures, they do not produce stress proteins.
Stress Proteins and CA • Insects cannot produce ‘stress response’ proteins if there is not enough oxygen to support metabolism. • We are not EXACTLY sure about the fruit, but we do fruit have a high capacity for anaerobic metabolism.
Scanning Metabolic Heat Rate 15 11 9 7 Heat Rate µW/mg FW 3 -1 -5
Isothermal Heat Rates 8 7 6 5 Heat Rate µW/mg FW 4 3 2 1 0 0 5 10 15 20 25 30 35 40 45 50 Temperature ° C
Codling Moth Pupal Respiration 0.06 Whole Range 0.05 uL CO2/mg/min = 0.001533 X Temp -0.00809 R2 = 0.977207 0.04 ul CO2/mg/min 0.03 0.02 10-30°C Range uL CO2/mg/min = 0.001942 X Temp -0.01618 0.01 R2 = 0.998422 0 5 10 15 20 25 30 35 40 Temperature °C
VAPOR 48°C 4 50 45 3 ul CO2/mg/min 40 TEMPERATURE °C MOIST 48°C 2 35 4 50 45 30 3 40 1 ul CO2/mg/min TEMPERATURE °C 25 2 35 30 1 0 20 25 0 50 100 150 200 250 300 0 20 0 50 100 150 200 250 300 TIME (min) TIME (min)
Importance of Heating Rate • We know that the faster the rate of heating, the shorter the time the insects have to be held at the final treatment temperature to kill them. • For example, CATTS at 12°C/h to final temperature of 46°C the core average temps have to be at 45°C for 30 min, while CATTS at 24°C/h to the same temperatures, cores only have to be at 45°C for 15 min.
40 Where... b0 = 22.4462 + 1.0486 SE b1 = -1.5745 + 0.09844 SE b2 = -0.2970 + 0.02339 SE R2 = 0.972 30 Time at Final Temp. (Hr) 20 10 0 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2 Heat Rate 42 44 46 Time at Final Temperature versus Heating Rate ln(LT95) = b0 + b1ln(heat rate) + b2 (treatment temperature)
Treatments against….. • Codling moth • Oriental fruit moth • Western Cherry fruit fly
Treatments developed for.. • Sweet Cherries • Apples • Peaches • Nectarines
Sweet Cherry CATTS • Two treatments have been developed and efficacy tests (5,000 killed, 0 survivors) against both CM and WCFF have been performed. • 25 min at 47°C with 1% O2, 15% CO2. • 45 min at 45°C with 1% O2, 15% CO2. • Fruit quality better than Methyl Bromide fumigated. • No commercial application has meet with specifications.