Báo cáo nghiên cứu khoa học " Benefits and difficulties of using petroleum spray oil " pot

Benefits and difficulties of using petroleum spray oil Oleg Nicetic and Debbie J Rae Centre for Horticulture and Plant Sciences, University of Western Sydney, Hawkesbury Campus, Richmond, NSW, Australia Presentation Overview • Spray oil defined • Emulsifiers • How spray oil works • PSO vs conventional pesticide • Phytotoxicity limiting factor for spray oil use • Spray oil as pest control agent on its own • Spray oil as an adjuvant • Use of spray oil for spray drift reduction Spray oil defined Spray oil nomenclature • White oil • Petroleum Spray Oil (PSO) • Mineral Spray Oil (MSO) • Agricultural Mineral Oil (AMO) • Horticultural Mineral Oil (HMO) • Narrow range vs broad range • Winter oil vs Summer Oil • PSOs are derived from lubricating oils. Three main types of molecules make up a spray oil: – Isoparaffins: provide most of the efficacy. – Naphthenes: less effective than isoparaffin. – Aromatics: a cause of plant damage. Median n- paraffin carbon number Viscosity 50% distillation temperature ASTM D 2887 Saybolt universal seconds (SUS) at 37.8ºC ASTM D 445 1.33 kPa (10 mm Hg) ASTM D 1160 101.33 kPa (760 mm Hg) ASTM D 447 ° C ° F ° C ° F nC19 331 628 nC20 344 651 nC21 ‘60’ 212 415 356 673 nC23 ‘70’ 224 435 380 716 nC24 ‘80’ 235 455 391 736 nC25 ‘100’ 247 476 401 754 nC27 421 790 • Oils can be light or heavy as measured by nCy (carbon number) – Generally range from nC21 (light) – nC25 (heavy) – Carbon number is related to the temperature 20 196 344 10% Values 24.3 243.5 394.5 50% 90% 27.4D 2887Equivalent n-paraffin carbon number (nCy) 265.5D 1160at 1.33 kPa 426D 2887 Distillation temperatures (C) at 101.33 kPa ASTM Method Key properties of SK base oil Other Values C P 74, C N 26, C A 0D 2140Molecular types (%) 0.8299D 1298Density at 15 °C  99.8 D 483Unsulfonated residue (% UR: minimum) - 24D 97Pour point (°C: maximum) 12.43 3.12 D 445Viscosity: Kinematic at 40°C at 100°C 71.1D 2161Viscosity: Saybolt at 37.8°C 340D 2502Mean molecular weight Emulsifier [...]... quantity of water and providing agitation while mixing  Be careful when making tank mix of oil and other pesticide specially when WP are added Tank should be nearly full with oil emulsion and then pre-mixed WP should be added As general rule it should not be more than 0.1kg of insoluble powder per 100 L of oil- water emulsion Stability of emulsion  Depending on quantity and type of emulsifier, emulsion of. .. with the target-the oil thinly coating the target, the water running off Water Oil Quick-break oil in water emulsions Oil remains on leaf surface or moves into leaf Water runs off Practical implication for using oils in field  Proper and constant agitation of the water -oil emulsion in the tank Temperature of the mixture in the tank or in the hose should never exceed 420 C  Adding oil to the adequate... species but usually tangerines and mandarins are most susceptible, pomelos and navel oranges are intermediate, sweet oranges, lemons and grapefruit are less susceptible Major causes of phytotoxicity – Presence of aromatics and impurities in oil – Amount of oil deposited on plant – High temperatures (particularly over 35°C) – Presence of moisture or heat stress – Plant type and growth stage – Poor agitation... phytotoxicity Oil soaking Oil soaking precursor to phytotoxicity  A particularly high risk for the use of oil is temperatures over 300 and relative humidity over 80%; conditions that are often present in the tropics  Oil viscosity decreases with increased temperature and it takes a long time for oil to dry so penetration into plant is very high and soaking can be observed after a single low concentration spray. .. single low concentration spray  When oil soaking is detected, oil sprays should be discontinued until oily spots disappear Unfortunately under humid tropical conditions it takes a long time for oily spots to diffuse from the fruits Leaf drop 12 sprays at 0.4% PSO 20 sprays at 0.2% PSO Leaf drop 70 a 35 60 a 30 ab 25 b 20 b 15 10 5 mean number of leaves +- SE mean number of leavs +- SE 40 50 a a a a a 40... functions including transpiration and movement of phytohormones  In the last 10 years progressively higher mean carbon number oils are being used and these oils more strongly affect plant physiological functions  Recommendations for spraying oil need to be more cautious and should never exceed recommended label dose and cumulative yearly dose  Recommended label dose and cumulative yearly dose vary.. .OIL OIL WATER EMULSIFIER WATER Oil + Emulsifier = Spray oil Typically PSOs contain from 0.35 to 2% emulsifiers However as PSO paraffinicity and unsulfonated residue (= hydrogen saturation) increase, it becomes more difficult to form oil- water emulsion thus the content of emulsifiers can increase to 6% Modern oils form quick breaking emulsions that ideally... costs, increases time of spraying and requires availability of lot of water • Overall in the short term PSO based IPM program is more expensive than conventional program but in the longer term they could have economic benefits Phytotoxicity Phytotoxicity is major limitation for use of oil as an insecticide, a deterrent or as an adjuvant Why PSO is phytotoxic  Every mineral oil interferes with plant... be sprayed 3-4 weeks before harvest  However if PSO is cumulated in fruit skin due to consistent soaking then colour can be affected even when spray is discontinued several months before harvest  When oil soaking was not present low concentration of 0.2% did not cause any colour deterioration even when oil was spray till the harvest Safe limits for use of PSO When PSO is used till the point of run-off... they cut the water inducing dry condition and then they use heavy watering to induce flowering If PSO sprayed at that time leaf can drop  More frequent sprays even at low concentration cause more leaf and fruit damage than single higher concentration spray  Generally PSO should not be sprayed during flowering under any condition Sunburn Sunburn 30 number of sunburned fruit +- SE 25 20 15 10 5 0 SK . adjuvant • Use of spray oil for spray drift reduction Spray oil defined Spray oil nomenclature • White oil • Petroleum Spray Oil (PSO) • Mineral Spray Oil (MSO) • Agricultural Mineral Oil (AMO) •. Benefits and difficulties of using petroleum spray oil Oleg Nicetic and Debbie J Rae Centre for Horticulture and Plant Sciences, University of Western Sydney, Hawkesbury. Spray oil defined • Emulsifiers • How spray oil works • PSO vs conventional pesticide • Phytotoxicity limiting factor for spray oil use • Spray oil as pest control agent on its own • Spray oil