Food irradiation is costly in terms of the energy utilized and the time spent, therefore, it is imperative to optimize it in order to avoid sub lethal dose or an overdose both of which have detrimental effects on the quality of fresh produce such as cantaloupe. The bacterial load in fresh cut cantaloupe flesh was quantified on the basis of growth and mobility over time, and used as the basis for targeted irradiation simulation. The bacterial growth was predicted using the Gompertz model, while a power law function was used for predicting the bacterial mobility. The microbiological structure of cantaloupe flesh was assessed using Transmission Electron, Scanning Electron, and Light Microscopy as a basis for understanding the mobility of the bacteria into the internal mesocarp tissues. A plate assay was also undertaken to determine the possibility of S. typhimurium producing cell wall degrading enzymes such as polygalacturonase to gain access into intact fresh cantaloupe tissues. S. typhimurium in fresh cut cantaloupe flesh has a lag phase duration of 7.76 hours and can reach a maximum population of 7.98 logs CFU/g in 30 hours. Cantaloupe flesh has a vast network of intracellular spaces through which the bacteria can move into the internal mesocarp tissues, particularly because S. typhimurium (LT2) does not produce any enzymes such as polygalacturonase which could be breaking down the cell wall binding structures as a mechanism for internalization into intact internal tissues. A theoretical bacterial inactivation dose estimate based on the experimentally determined D10-value and the bacterial population was used to simulate irradiation treatment of the cantaloupe flesh samples using a 10MeV electron beam irradiator (LINAC) to establish the best treatment. The optimal 10 MeV electron beam irradiation treatment for S. typhimurium internalized in fresh cut cantaloupe samples for 30 hours was determined to be a double beam with 0.5 cm attenuation of Lucite (Trademark) at the top and 3.3 cm at the bottom.

Cantaloupes for fresh market were studied as an alternative crop for the farmers in the Safford valley. Three varieties were tested with the top variety yielding over 1000 cwt per acre. The quality of the fruit was good, but work needs to be done to determine if there is a slot in the market for fruit from this area.

Powdery mildew of cantaloupe, caused by Sphaerotheca fuliginea, is a perennial and often devastating disease in Arizona. During 1987 and 1984 potential new fungicides were evaluated in field trials for disease control. In 1987, Bayleton, Rally and Spotless provided significant disease control. In 1984, Rally and Spotless significantly reduced development of powdery mildew, while Bayleton and Tilt were less effective. Uneven development of powdery mildew within the plot may partially explain the apparent lack of significant disease control in 1988 by Bayleton and Tilt.

No description available.

Powdery mildew of cantaloupe, caused by the fungus Sphaerotheca fuliinea, is a perennial and often serious disease in Arizona. In 1989, potential new fungicides were evaluated for disease control in a field trial. All tested materials provided significant control when compared to untreated plants. Of the compounds tested only Bayleton currently is registered for use on cantaloupe. Rally, which performed extremely well in this test; should be available for use on cantaloupe in the near future.

No description available.

Leaf drop of lettuce, caused by the plant pathogenic fungi Sclerotinia sclerotiorum and S. minor. occurs every year in some lettuce fields in Arizona. When environmental conditions are favorable, disease incidence and resulting crop loss can be significant. During the 1990-1991 lettuce season in western Arizona, different fungicides and rates of materials were evaluated in the field for disease control. All tested materials increased yields compared to not using any fungicide for disease control.

A study was conducted to determine the effects of repeated insecticide applications on leaf niner and parasitoid populations on spring melons. After four applications, none of the insecticides induced large build-ups of leafminer larvae. A new material, AC 303630, was very effective in maintaining low numbers of pupae. However, the results of this preliminary test indicate that all insecticides tested had a negative impact on the parasitoid population. In general, in the absence of insectcides, parasitoids were capable of maintaining L. sativae populations at low levels in the experimental plots.

No description available.

No description available.