Roberto G. Lopez

Are Consumers Willing to Pay More for Biodegradable Containers Than for Plastic Ones? Evidence from Hypothetical Conjoint Analysis and Nonhypothetical Experimental Auctions

This study used and compared hypothetical conjoint analysis and nonhypothetical experimental auctions to elicit floral customers’ willingness to pay for biodegradable plant containers. The results of the study show that participants were willing to pay a price premium for biodegradable containers, but the premium is not the same for different types of containers. This article also shows the mixed ordered probit model generates more accurate results when analyzing the conjoint analysis Internet survey data than the ordered probit model.

Proposed product label for electric lamps used in the plant sciences

Electric lamps are widely used to supplement sunlight (supplemental lighting) and daylength extension (photoperiodic lighting) for the production of horticultural crops in greenhouses and controlled environments. Recent advances in light-emitting diode (LED) technology nowprovide the horticultural industrywith multiple lighting options. However, growers are unable to compare technologies and LED options because of insufficient data on lamp performance metrics. Here, we propose a standardized product label that facilitates the comparison of lamps across manufacturers. This label includes the photosynthetically active radiation (PAR) efficacy, PAR conversion efficiency, photon flux density output in key wave bands, as well as the phytochrome photostationary state (PSS), red/far red ratio, and graphs of the normalized photon flux density across the 300–900 nm wave band and a horizontal distribution of the light output.

Effects of Selected Fertilizers on the Life History of Bemisia tabaci (Hemiptera: Aleyrodidae) Biotype B

ABSTRACT We tested the effects among a purportedly sustainable water-soluble fertilizer, a conventional water-soluble fertilizer, an alternation of these, a controlled-release fertilizer, and a clear water control on the life-history traits of sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae; = Bemisia argentifolii Bellows & Perring) biotype B reared on poinsettia (Euphorbia pulcherrima Willdenow ex Klotzch). Free amino acids in petioles were measured to estimate plant nutrient assimilation and phloem nutritional quality for B. tabaci biotype B. The sustainable fertilizer produced plants with the highest concentration of amino acids. In contrast, fecundity of whiteflies was lowest in plants treated with the sustainable fertilizer and the water control. The relationship between total amino acids in phloem and survival was significantly quadratic, with the highest survival at intermediate levels. Fecundity, however, was negatively correlated with total amino acid content of the maternal host plant. Variation in total amino acid concentration in petioles of plants treated within fertilizer treatments makes it difficult to predict whether a particular fertilizer will produce plants with enough amino acids to deleteriously affect both survivorship and fecundity and yet yield a plant of good quality. Despite this limitation, we can conclude that the use of this sustainable fertilizer will not cause increases in whitefly populations relative to plants fertilized with water-soluble and slow-release fertilizers that deliver the same level of nitrogen to the plant.

Control of Morphology by Manipulating Light Quality and Daily Light Integral Using LEDs

In northern latitudes, supplemental lighting is utilized to increase the photosynthetic daily light integral in greenhouses during the winter months, which can fall as low as 1–5 mol m−2 d−1. Traditionally, supplemental lighting has been provided by high-intensity discharge (HID) lamps, but light-emitting diode (LED) technologies are now available for many greenhouse applications. The use of LEDs for supplemental lighting can be beneficial because wavelengths of light can be selected for applications such as the control of plant growth, development, morphology, and leaf color. However, delivering these precise wavelengths at moderately low intensities with ambient light already present in the greenhouse may prove ineffective at eliciting desired morphological characteristics. Regardless, LEDs have proven to be a viable option to provide supplemental lighting in the many controlled environments.