The objective of this research was to investigate whether a controlled atmosphere established inside a high temperature forced air chamber could enhance the mortality of the most heat-resistant life stage of Mexican fruit fly larvae (Anastrepha ludens Loew) and thereby reduce the amount of time grapefruit (Citrus paradisi Macf.) harvested from Mexican fruit fly-infested regions must be exposed to high-temperature forced air to achieve quarantine security. The mortality of third instar larvae treated on diet was significantly higher after exposure to 1% oxygen or 1% oxygen enriched with 20% carbon dioxide than it was in either air or air enriched with 20% oxygen. Reducing the amount of oxygen in air from 21% to 1% during forced air heating at 46°C, reduced the exposure time required for 100% kill of larvae inside artificially infested grapefruit from 5 hours to 3.5 hours. Inconsistent fruit quality results warrant further study to optimize controlled atmosphere conditions during heating. Based upon relative levels of carbon dioxide inside the grapefruit during heating, fruit respiration during heating in 1% oxygen was lower than during heating in air. Results from this research suggest that reducing the amount of oxygen in a high temperature forced air chamber during heating can reduce the amount of time fruit must be exposed to heat for quarantine security against Mexican fruit fly.
A precise temp control apparatus is described which is useful for studying plant responses between +50° and -100°C.
The rate of leaf unfolding was determined for Easter lily (Lilium longiflorum Thunb.) ‘Nellie White’ grown at day and night temperatures ranging from 14° to 30°C. In this temperature range, rate of leaf unfolding was a linear function of average daily temperature; i.e., the effect on rate of leaf unfolding for day temperature was the same as for night temperature. The function determined was: leaves unfolded per day = −0.1052 + (0.0940 × average daily temperature). Isopleth plots were developed to describe day and night temperatures required for specific rates of leaf unfolding under 8-, 10-, and 12-hr day temperature periods.
Time and temp requirements for floral induction in the Amazon lily were found to be 12 days at 29.4°C (85°F) or 3 weeks at 19.4°C (67°F). Greater numbers of bulbs flowered, however, when heated for 16 days at 29.4°C or 3 weeks at 20.6°C (69°F). No detrimental effects, as indicated by percent flowering and flowers per scape, were apparent when bulbs were heated for 4, 5, 6, 7, 8, or 9 weeks at 29.4°C. Total production time was increased as treatment period was extended, but appeared to be definitely modified by season. Days after heating to first flower progressively decreased and total flowers per scape increased as growing conditions improved in spring. The fall crop showed an opposite response.
Alternatives to ethoxyquin (Etq) are needed for controlling superficial scald of ‘Anjou’ european pears (Pyrus communis) during long-term storage. The current commercial standard storage conditions [Etq + −1 °C + controlled atmosphere (CA) with 1.5 kPa O2] reduced scald occurrence compared with control fruit (−1 °C + CA) during 6–8 months storage. At 1 °C in air, 1-methylcyclopropene (1-MCP) fumigation at 0.15 µL·L−1 at harvest was more efficient on reducing scald than Etq but did not prevent scald during 6–8 months storage. The 1-MCP-treated fruit at 1 °C in air developed their ripening capacity at 20 °C following 6–8 months storage but had deceased shipping ability (softening and yellowing of fruit). Although Etq inhibition of scald was associated with the inhibition of α-farnesene oxidation to conjugated trienols (CTols); 1-MCP reduced α-farnesene synthesis and thereby the availability of substrate to oxidize to CTols. CA storage at 1.5 kPa O2 totally prevented scald and retarded the loss of shipping ability without affecting the ripening capacity of 1-MCP-treated fruit at 1 °C through further decreases in the syntheses of ethylene, α-farnesene and CTols during 6–8 months storage. In addition, 1-MCP prevented a CA-induced disorder, pithy brown core (PBC), in ‘Anjou’ pears possibly through enhancing an oxidative/reductive metabolic balance during extended storage. In conclusion, the combinations of 1 °C + 1-MCP + CA is a potential commercial alternative to Etq for scald control while allowing the 1-MCP-treated ‘Anjou’ pears to recover ripening capacity during the shelf life period after 6–8 months storage.
, the majority of hydroponic farmers are growing peppers in non-temperature-controlled tunnels, which rely on natural ventilation by opening the doors and flaps. This often results in poor plant growth, low yield, and poor fruit quality during the hot
, FL), and United Parcel Service (Atlanta, GA) to deliver flowers to their customers. However, there is often a lack of proper temperature control when using rapid transit carriers, and flowers can be exposed to high and fluctuating temperatures. This
performed on a thermal gradient table, which can generate many temperatures simultaneously ( Welbaum et al., 2016 ). However, experiments involving larger plant parts, such as cut stems used in forcing experiments of woody perennials, require temperature
achieved with this temperature control concept/strategy. High early-season yield is especially important in greenhouse vegetable production in cold regions because the market price is usually much higher before the field products can reach the market
easily adjusted. Cost factors are important for evaluating the economy of cell tray seeding. Taking into account the costs of temperature control units capable of lowering the temperature to 15 °C to 20 °C in agricultural facilities, 30 °C/3 d/ 55