How to overcome the egg-weakness of sulfuryl floride –
Transcription
How to overcome the egg-weakness of sulfuryl floride –
How to overcome the egg-weakness of sulfuryl floride – combinations of control methods Christoph Reichmuth and Dagmar Klementz Federal Research Institute for Cultivated Plants, Julius Kühn-Institute (JKI) Institute for Ecological Chemistry, Plantanalysis and Stored Product Protection Berlin, Germany MBAO, Postharvest Session V, November 12, 2008, Orlando Fl. Reichmuth and Klementz Vision Consequence of laboratory and field data: Necessity to modify the actual fumigation schedules for SF to ensure complete control (incl. egg stages) of some pest insects like especially the Flour Beetles Tribolium spec. MBAO, Postharvest Session V, November 12, 2008, Orlando Fl. Reichmuth and Klementz Aim Identify approach(es): include all egg stages of tolerant species into the control program with SF. Use available information! MBAO, Postharvest Session V, November 12, 2008, Orlando Fl. Reichmuth and Klementz Today‘s situation Germany (also elesewhere?) 2006-2008: nearly 50% of checked SF mill treatments left considerable numbers of surviving pest insects behind (eggs survived within weeks) (ref. ASSOCIATION of GERMAN MILLERS Also in the UK (e.g. Dr. Kenneth MILLS) found surviving pest insects despite strict dosage schedules. MBAO, Postharvest Session V, November 12, 2008, Orlando Fl. Reichmuth and Klementz Why this problem? Adoption of theoretical laboratory mortality data for practical field use: much higher safety margins required: - variation of temperature/leakage - estimation of the real concentration where the insects hide - gas and heat convection within the object} MBAO, Postharvest Session V, November 12, 2008, Orlando Fl. Reichmuth and Klementz Possible approaches: - increased dosage of sulfuryl fluoride or - combination of sulfuryl fluoride with 1: heat 2: phosphine 3: carbon dioxide 4: hydrogen cyanide 5: pulsed fumigation 6 other (e.g. like PPO+CO2) MBAO, Postharvest Session V, November 12, 2008, Orlando Fl. Reichmuth and Klementz Basic considerations species stages eggs Tribolium castaneum post embryonic full lethal ct product in reference gh/m³ at 25°C 1,669 113 BELL et al., 2003 Question: Which ct product is appropriate (LD 99.9%, eggs, larvae, pupae and adults) for practical field conditions?? {BELL (1988): 5g/m³ MB sufficient in the laboratory; field: 20g/m³ for structural } MBAO, Postharvest Session V, November 12, 2008, Orlando Fl. Reichmuth and Klementz Basic considerations species stages eggs Tribolium castaneum post embryonic Full lethal ct product in gh/m³ at 25°C 1,669 113 reference BELL et al., 2003 Question: Which ct product is appropriate? Correction factor of about 3 reasonable: 4,500gh/m³ instead of 1,669gh/m³ for all stages or 300gh/m³ instead of 113gh/m³ for post embryonic stages. MBAO, Postharvest Session V, November 12, 2008, Orlando Fl. Reichmuth and Klementz Solution 1 SF and heat (>35 C) Advantage: within the label Disadvantage: heat damage, distribution Costs: increased by about factor 2* compared to SF alone _________________________________ * this and the follwing fiures are raw estimates! MBAO, Postharvest Session V, November 12, 2008, Orlando Fl. Reichmuth and Klementz Solution 2 SF and phosphine Advantage: within label Disadvantage: corrosion, expanded down time Cost: Factor 1.5* compared to SF alone MBAO, Postharvest Session V, November 12, 2008, Orlando Fl. Reichmuth and Klementz Solution 3 SF and carbon dioxide Advantage: Combination with inert atmospheres, possibility to combine with heat Disadvantage: Expected long exposure Cost: Fairly higher than SF alone MBAO, Postharvest Session V, November 12, 2008, Orlando Fl. Reichmuth and Klementz Solution 4 SF and hydrogen cyanide Advantage: little gas of each Disadvantage: label, two compounds, worker safety Cost: not necessarily more since only small amounts of both fumigants necessary MBAO, Postharvest Session V, November 12, 2008, Orlando Fl. Reichmuth and Klementz Av. number of survivors of all life stages of Tribolium castaneum (Tc) and Sitophilus granarius (Sg): 48 h sulfuryl fluoride (SF) alone, hydrogen cyanide (HCN) alone, or a combination of SF and HCN, 23°C, 65% r.h.# SF: 20g/m³ SF: 20g/m³ + no SF 1.5g/m³ HCN no HCN 1.5g/m³ HCN average number of survivors, counted as adults (Tc/Sg) after 12 weeks 4/4 0/0 6/9 Untreated: 40/71 #Patent of K.MBAO, BÄUMERT andSession H.-J. BELT, 2002,12, DE2008, 10110570A1 Postharvest V, November Orlando Fl. Reichmuth and Klementz Solution 5 + SF and repeated treatment in intervals (Pulsed Fumigation)+ Advantage: no other chemical, within the label Disadvantage: longer down time, MRL problem(?) Cost: nearly factor 2, depending on the sealing necessities, may be less since the single fumigation requires less SF to control susceptible stages _________________________________ European Patent by Binker company MBAO, Postharvest Session V, November 12, 2008, Orlando Fl. Reichmuth and Klementz Pulsed Fumigation, basic considerations species stages eggs Tribolium castaneum post embryonic Full lethal ct product in gh/m³ at 25°C reference 1,669 113 BELL et al., 2003 Question: Which ct product and time interval (length of pulse, how many days? between the two fumigations is appropriate (LD99.9%, larvae, pupae and adults) for practical field conditions (safety factor?)?? Reichmuth and Klementz MBAO, Postharvest Session V, November 12, 2008, Orlando Fl. Pulsed Fumigation, basic considerations species stages eggs Tribolium castaneum post embryonic Full lethal ct product in gh/m³ at 25°C reference 1,669 113 BELL et al., 2003 Question: Which ct product (30g for 10h or 10g for 30h) and time interval (length of pulse, how many days? ct=300gh/m³?) between the two fumigations is appropriate (LD99.9%, larvae, pupae and adults) for practical field conditions (safety factor aboutReichmuth 3)?? and Klementz MBAO, Postharvest Session V, November 12, 2008, Orlando Fl. Pulsed fumigation, dosage SF concentration ing/m³ 100 300gh/m³ Safety margin ca. 3 for leakage, uneven gas distribution, temperature differences 113gh/m³ field field ct = 300gh/m³ 10 laboratory laboratory ct = 113gh/m³ 1 0 10 24 30 48 72 Fumigation time in hours Model T. cast. 25°C MBAO, PostharvestPossible Session V, November 12, (t 2008, Orlando Fl. obtain a ct product Reichmuth and dosages and c) to of Klementz 300gh/m³ Pulsed fumigation, dosage SF concentration ing/m³ 100 300gh/m³ Safety margin ca. 3 for leakage, uneven gas distribution, temperature differences 30 113gh/m³ field field ct = 300gh/m³ 10 laboratory laboratory ct = 113gh/m³ 1 0 10 24 30 48 72 Fumigation time in hours Model T. cast. 25°C MBAO, PostharvestPossible Session V, November 12, (t 2008, Orlando Fl. obtain a ct product Reichmuth and dosages and c) to of Klementz 300gh/m³ Pulsed fumigation, dosage SF concentration ing/m³ 100 300gh/m³ Safety margin ca. 3 for leakage, uneven gas distribution, temperature differences 30 113gh/m³ field field ct = 300gh/m³ 10 laboratory laboratory ct = 113gh/m³ 1 0 10 24 30 48 72 Fumigation time in hours Model T. cast. 25°C MBAO, PostharvestPossible Session V, November 12, (t 2008, Orlando Fl. obtain a ct product Reichmuth and dosages and c) to of Klementz 300gh/m³ Pulsed fumigation, pulse length Development of stages, model for Tribolium castaneum eggs 30°C larvae pupae t30 adults 20°C t20 0 10 20 30 40 50 60 70 developmental timeOrlando in days MBAO, Postharvest Session V, November 12, 2008, Fl. 80 90 100 Reichmuth and Klementz Pulsed fumigation, length of time (pulse) between two consecutive fumigations with 300gh/m³: 14 days 1800 1600 hatch of larvae with lower tolerance eggs larvae pupae adults 1400 ct in gh/m³ 1200 1000 800 ct to control post embryonic stages with safety margin 600 400 300 ct to control post embryonic stages 200 0 0 10 20 30 MBAO, Postharvest Session V, November 12, 2008, Orlando Fl. Time in days first fumigation second fumigation 40 50 Reichmuth and Klementz 60 Pulsed fumigation, length of time (pulse) between two consecutive fumigations with 300gh/m³: 14 days 1800 1600 hatch of larvae with lower tolerance eggs larvae pupae adults 1400 ct in gh/m³ 1200 1000 800 ct to control post embryonic stages with safety margin 600 400 300 ct to control post embryonic stages 200 0 0 10 20 30 MBAO, Postharvest Session V, November 12, 2008, Orlando Fl. Time in days first fumigation second fumigation 40 50 Reichmuth and Klementz 60 Conclusions to overcome the egg-weakness of SF by - increased SF dosage (limitation label and cost) or Combination with 1: heat 2: phosphine 3: carbon dioxide 4: hydrogen cyanide 5: pulsed fumigation 6: others? *but promising clumsy* limited expensive cheap but clumsy* time consuming* MBAO, Postharvest Session V, November 12, 2008, Orlando Fl. Reichmuth and Klementz Any problem with SF? Its the insect egg, stupid! (free after former US President Bill Clinton) MBAO, Postharvest Session V, November 12, 2008, Orlando Fl. Reichmuth and Klementz