Integration of the predatory miteNeoseiulus californicuswith petroleum spray oil treatments for control ofTetranychus marianaeon eggplant

The effects of three highly refined petroleum spray oils and of ambient vapor pressure on net CO2 assimilation (A) and stomatal conductance of water vapor (gs) of single grapefruit (Citrus paradisi Macf.) leaves were investigated. Overall, gs of various-aged leaves was decreased by a large leaf-to-air vapor pressure difference (VPD). In the first experiment, oils with midpoint distillation temperatures (50% DT) of 224, 235, and 247C were applied with a hand atomizer at concentrations of 0, 1%, and 4% oil emulsions in water and 100% oil, all with 0.82% surfactant (by volume). There was a tendency for oils of the two higher DT to decrease net gas exchange during a subsequent 12 days, but significant differences could not be attributed to oil DT. Both A and gs were reduced by the two higher concentrations of oil mixtures. In the second experiment, a commercial airblast sprayer was used to apply the 224C oil at 4% or the 235C oil at 2% and 4% mixtures plus surfactant under field conditions. There were no significant effects of oil treatments on net gas exchange of leaves either measured under moderate VPD outdoors 1 day after spraying or under low VPD in the laboratory 2 days after spraying. No visible phytotoxic symptoms were observed in either experiment.

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Ozone Air Pollution Increases Petroleum Spray Oil Phytotoxicity

HortScience ◽

10.21273/hortsci.29.2.93 ◽

1994 ◽

Vol 29 (2) ◽

pp. 93-94 ◽

Cited By ~ 1

Author(s):

W.A. Retzlaff ◽

W.W. Barnett ◽

L.E. Williams ◽

T.M. DeJong

Keyword(s):

Aqueous Solution ◽

Air Pollution ◽

Partial Pressure ◽

Spider Mites ◽

Atmospheric Ozone ◽

Spray Application ◽

Japanese Plum ◽

Prunus Salicina ◽

Partial Pressures ◽

Petroleum Spray Oil

Japanese plum (Prunus salicina Lindel. `Casselman') trees exposed to three atmospheric ozone partial pressure treatments were sprayed with a summer application of Volck Supreme oil (1% aqueous solution) to control an outbreak of spider mites (Tetranychus spp.). Phytotoxic effects were observed on the foliage of trees in the plots exposed to ambient or higher atmospheric ozone partial pressures 5 days following spray application. Foliage on trees exposed to 0.044 and 0.081 μPa·Pa-1 ozone [12-h mean (8 Apr. to 12 June 1992)] partial pressures developed water spotting and more foliage abscission than trees exposed to charcoal-filtered air (0.024 μPa·Pa-1 ozone). Thus, ozone air-pollution stress may predispose plants to increased phytotoxicity from summer oils.

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Compatibility of a petroleum spray oil and foliar zinc fertilisers

Australian Journal of Experimental Agriculture ◽

10.1071/ea9960331 ◽

1996 ◽

Vol 36 (3) ◽

pp. 331

Author(s):

MC Hodgkinson ◽

DC Joyce ◽

AP Mackey ◽

DS Sagatys ◽

TS Schmiede ◽

...

Keyword(s):

Chlorophyll Fluorescence ◽

Inductively Coupled Plasma ◽

Atomic Emission ◽

Emission Spectrometry ◽

Zn Deficiency ◽

Acid Extraction ◽

Plasma Atomic Emission Spectrometry ◽

Zinc Deposition ◽

Solvent Washing ◽

Petroleum Spray Oil

The performance of 7 commercial zinc (Zn) foliar nutrients sprays, based on sulfate (Top ZM), hydrated sulfate (Pivot Zinsol; Pivot Mangasol-zinc), oxide (Phosyn Zintrac), and ligninsulfonate (Spray-gro Zn PC; Spray-gro Zn/Mn PC; SJB), were assessed with and without addition of a horticultural petroleum spray oil (PSO), Ampol D-C-Tron NR. Foliar Zn deposition and absorption was quantified by Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES) after solvent washing and acid extraction. Effects on photosystem II were measured by chlorophyll fluorescence. Although none of the Zn sprays were soluble in PSO, all but Zn oxide could be suspended adequately before spraying. A partial emulsion break occurred with Zn sulfate and hydrated sulfates. All treatments increased the Zn content of leaves by an amount likely to alleviate Zn deficiency. Addition of PSO decreased deposition and absorption of Zn when used with the inorganic formulations or with Spray-gro Zn PC. Zinc deposition and absorption were increased by PSO in Spray-gro Zn/Mn PC, and were unaffected by PSO in SJB. Plant chlorophyll fluorescence and phosphorus content did not differ among treatments. The ligninsulfonates Spray-gro Zn/Mn PC and SJB were most compatible with Ampol D-C-Tron NR, and had relatively low potential for Zn pollution of the environment.

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