Carbon Dioxide Fumigation to Shorten Cold Disinfestation Treatments for Thaumatotibia leucotreta (Lepidoptera: Tortricidae) in Citrus Fruit

Author(s):  
Tim G Grout ◽  
Kim C Stoltz

Abstract Although elevated levels of carbon dioxide have been used in controlled atmosphere treatments with low oxygen levels for a number of deciduous crops, the use of much higher concentrations of carbon dioxide followed by a short cold treatment for citrus was only suggested as a viable option for disinfestation in 2005. Carbon dioxide alone, for a period of 24 h at concentrations up to 70% in air caused variable levels of mortality of Thaumatotibia leucotreta (Meyrick) larvae in citrus, but never completely controlled this pest. The susceptibility to carbon dioxide appeared to vary more with the batch of T. leucotreta eggs than with different citrus cultivars. By following CO2 fumigation with a short cold treatment, complete control of this pest was achieved and the results with sequential treatments were more consistent. The efficacy of the combined treatment was reduced when it took ≥12 h to move fruit after fumigation into a cold room at 2°C, or if the temperature was not reduced below 12°C within 24 h after fumigation. In these cases, the benefit of the short cold treatment was lost and mortality was similar to CO2 fumigation alone. These results hold promise for the development of a shorter commercial treatment to meet quarantine restrictions against this pest in citrus.

HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 512B-512
Author(s):  
Krista C. Shellie

Green mold, a predominant disease of citrus fruit, develops when spores of Penicillium digitatum infect extant wounds in fruit epidermal tissue. Development of green mold during shipping limits the distance grapefruit can be surface transported. The objective of this research was to evaluate whether altering the atmosphere during refrigerated storage could suppress development of green mold. In the first two experiments, growth of green mold was evaluated after fruit were stored in ultra-low oxygen (0.05 or 1 kPa) at 14, 16, or 18 °C for up to 21 days. In the last two experiments, grapefruit were stored for 14 or 21 d at 12, 13, or 14 °C in atmospheres containing 2, 5, or 10 kPa oxygen with or without 2, 5, 10, or 20 kPa carbon dioxide. In all experiments, grapefruit were inoculated with 10 or 20 μL of a spore suspension of P. digitatum. Decay progression after storage was monitored by measuring the diameter of the lesion in cm at the demarcated site of inoculation or by subjectively rating percent decayed fruit surface area. Grapefruit not inoculated with P. digitatum had no visible symptoms of green mold. Grapefruit stored under controlled atmosphere had less fruit surface covered with mycelium (5% to 64%) than grapefruit stored in air. Inoculated grapefruit stored in 0.05 kPa oxygen for up to 14 d at 14 or 18 °C had no visible symptoms of green mold upon removal from cold storage, but developed a characteristic green mold lesion after 5 additional days of storage in air at ambient temperature. Results suggest that refrigerated controlled-atmosphere storage combined with wax and a fungicide can enhance control of green mold during shipping.


1918 ◽  
Vol 27 (3) ◽  
pp. 399-412 ◽  
Author(s):  
H. G. Martin ◽  
A. S. Loevenhart ◽  
C. H. Bunting

Exposure of rabbits to an atmosphere of low oxygen content results in a stimulation of the cardiorespiratory systems, in an extension (hyperplasia) of red bone marrow and probably of a thyroid hyperplasia, with the further production of hydropic and hyaline degeneration in the cells of the parenchymatous organs. An atmosphere of high carbon dioxide and normal oxygen content produces, however, a stimulation of the cardiorespiratory systems, but no marrow extension and, in the concentrations used, but slight hydropic degeneration in the parenchyma of the glandular organs.


2021 ◽  
Vol 2119 (1) ◽  
pp. 012101
Author(s):  
I G Donskoy

Abstract One of the main problems in the use of solid fuels is inevitable formation of significant amounts of carbon dioxide. The prospects for reducing CO2 emissions (carbon capture and storage, CCS) are opening up with the use of new coal technologies, such as thermal power plants with integrated gasification (IGCC) and transition to oxygen-enriched combustion (oxyfuel). In order to study the efficiency of solid fuel conversion processes using carbon dioxide, thermodynamic modeling was carried out. Results show that difference between efficiency of fuel conversion in O2/N2 and O2/CO2 mixtures increases with an increase in the volatile content and a decrease in the carbon content. The effect of using CO2 as a gasification agent depends on the oxygen concentration: at low oxygen concentrations, the process temperature turns out to be low due to dilution; at high oxygen concentrations, the CO2 concentration is not high enough for efficient carbon conversion.


1955 ◽  
Vol 184 (1) ◽  
pp. 202-208 ◽  
Author(s):  
Dixon M. Woodbury ◽  
Lawrence T. Rollins ◽  
Joyce R. Henrie ◽  
Joseph C. Jones ◽  
Tada Sato

The influence of various concentrations of carbon dioxide and oxygen on the pattern of maximal electroshock seizures (MES), on pentylenetetrazol (Metrazol)-induced seizures, and on recovery time (RT50) from MES has been studied in mice. The major results are summarized as follows: Increasing the concentration of carbon dioxide in 20% oxygen resulted in marked changes in the MES pattern. The duration of the tonic flexor component was increased, and the duration of the tonic extensor component and of the entire tonic phase was decreased; the ratio of flexion to extension was increased markedly. These changes indicate an anticonvulsant effect of carbon dioxide. Carbon dioxide in a concentration of 15.6% protected 50% of mice against a 97% convulsant dose (CD97) of Metrazol. Hypoxia, induced by inhalation of 15 or 10% oxygen, decreased the duration of the tonic flexor component and increased the duration of the tonic extensor component of the MES; the duration of the entire tonic phase was increased; the ratio of flexion to extension was slightly decreased. These changes indicate an excitatory effect of low oxygen concentrations on the brain, under the stated conditions. Hyperoxia, induced by inhalation of 50, 75 or 90% oxygen, in contrast to hypoxia, resulted in effects on MES similar to those produced by inhalation of carbon dioxide. The RT50 was slightly, but not significantly, decreased by hypoxia (15% oxygen), unchanged by hyperoxia (50% oxygen), and markedly increased by an increase in carbon dioxide concentration. Carbon dioxide (5 and 10%) combined with hypoxia (10% oxygen) produced effects on MES pattern and RT50 similar to those produced by carbon dioxide in 20% oxygen.


Insects ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 802
Author(s):  
Farhan J.M. Al-Behadili ◽  
Manjree Agarwal ◽  
Wei Xu ◽  
Yonglin Ren

The Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), is one of the most damaging horticultural insect pests. This study used a low-oxygen/high-nitrogen bioassay to control C. capitata. Two low-oxygen treatments were applied (0.5% O2 + 99.5 N2 and 5% O2 + 95% N2) to C. capitata eggs and 1st, 2nd and 3rd instar larvae from 0 to nine days on a carrot diet at 25 °C; 70—75% RH. The pupariation, adult emergence, and sex ratios of survived flies were examined. The results demonstrate that increased mortality of all tested life stages correlated with increased exposure times at both levels of low-oxygen treatments. Complete control of eggs was achieved after eight days and nine days for larvae using 0.5% O2 at 25 °C; 70–75% RH. The 3rd instar was the most tolerant stage, while the egg was the most susceptible stage to the low-oxygen environment. There were no significant differences in sex ratios between emerged adults after low-oxygen and control treatments. The present work demonstrates and confirms the mortalities of C. capitata caused by low-oxygen treatment, which may help develop new postharvest strategies to control this destructive fruit fly pest.


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