Tesis (Ingeniero agrónomo administrador)--Instituto Tecnológico y de Estudios Superiores de Monterrey. / Bibliography: leaves 71-74.

Th. 3e cycle--Sci. agron.--Nancy--I.N.P.L., 1983.

Th. doct.-ing.--Sci. et tech. en prod. vég. et qualité des produits--Toulouse--I.N.P., 1984. N°: 327.

With her very first book Nathalie Sarraute insisted upon the importance of the tropism. Though most critics acknowledge its importance, only one has used it as a key to his study. This thesis proposes that the tropism is central to the structure of Sarraute’s work and specifically to that of Les Fruits d'Or. The study presupposes that the text of the novel is the ultimate, objective source of evidence. Following the suggestion of a number of French structuralist critics, a distinction is drawn between narrative and fiction, and the elements of each of these aspects of the novel are examined. In Chapter 1, "Narrative,” are studied Narrative Point of View, Narrative Structure, and Style; in Chapter 2, "Aspects of the Fiction," appear the subsections, Plot, Character, Space, and Time. Because of the nature of Les Fruits d'Or a further chapter was needed to explore the content of the work, so that Chapter 3, "Thematic Structure," deals with the principal themes and their interrelationship. The word "tropism" describes the process of adaptation of an organism to its environment. Sarraute uses it to explore the interior movements which her characters experience in responding to events. Thus we find that the external event becomes no more than a catalyst to release those sensations which form the substance of the work. The narrative point of view enables the reader to experience the sensation simultaneously with the character, while the structure reveals a cyclical pattern of conflict and harmony corresponding to that of the tropism. In the style we find both the attempt to create immediacy of dialogue and a language appropriate to the expression of sensation. With the vast expansion of the narrative, the fictional aspects of Les Fruits d'Or become subsidiary. The plot is a skeleton upon which to mould the flesh of the narrative, but it conforms, with its pattern of action and reaction, to the tropism. The characters lose fictional individuality and become extensions of a uniform psychology, which is perceived in terms of stimulus and response. Space and time have lost almost all fictional existence and have become psychological determinants accounting for the pervading sense of enclosure and of mechanical recurrence within the vast, new space-time of the tropistic movements. The "mise en abime" at the centre of Les Fruits d'Or creates a triple level of meaning which is illustrated in three themes. The first, "Art,” corresponds to the plot and describes satirically the cyclical rise and decline of a novel. At the second level, "Appearance and Reality” illustrates the conflict, central to the work, between the visible and the felt, the hard and the soft. The theme, "Individual and Society," reveals the common aspiration for a harmony which is eternally elusive. Relating these themes we find, once again, the pattern of the tropism, a cyclical movement of stimulus and response in which appear the basic rhythms of conflict and re-integration. Our concentration upon the structure of the tropism leads, in conclusion, to the high-lighting of certain aspects of Sarraute's work. The tropism is both a vision of man's inner existence and a vehicle for its expression. It also presents, however, a pessimistic and deterministic view of the world. Demonic imagery predominates but the apocalyptic is seen as a mere sham. Authenticity is never more than a flickering hope. The tropism is common to all Sarraute's work, and her exploration of man's psychological depths is not unique in literature. Her most important contribution to the novel lies in her vision of the inner world as man's true realm of action and in her provision of access to that world by means of the tropism. / Arts, Faculty of / French, Hispanic, and Italian Studies, Department of / Graduate

Phytophthora parasitica and P. citrophthora are routinely recovered from diseased citrus groves in Arizona. Stem sections were collected monthly from Citrus macrophylla, rough lemon, .sour orange, Cleopatra mandarin, Troyer citrange and Citrus volkameriana. Stem pieces were wounded, inoculated with mycelium of P. parasitica or P. citrophthora, then incubated for 7 days at 21° C in moist chambers. For all tested rootstocks, the smallest cankers were produced on tissue collected in December, January and February, the winter dormancy period for citrus in Arizona. The period of higher susceptibility ranged between March through November, depending on the rootstock tested. Apparently, these six citrus rootstocks possess seasonal differences in their susceptibility to P. parasitica and P. citrophthora.

Gummosis caused by Phytophthora parasitica and P. citrophthora is a serious problem in Arizona citrus groves. In a 15-year-old Orlando tangelo planting at the Yuma Mesa Agricultural Center, a 20 cm section of trunk on each tree was painted with phosphorous acid, metalaxyl or fosetyl-Al. After treatment, pieces of bark were periodically removed from within, as well as below, the treated area and inoculated with P. parasitica and P. citrophthora. After 117 days, both Phytophthora species were inhibited on bark treated with phosphorous acid, metalaxyl or fosetyl-Al. Canker development was also reduced on bark tissue sampled 10 cm below the site of treatment. The results suggest that trunk application of phosphorous acid, metalaxyl or fosetyl-Al can provide effective protection against Phytophthora gummosis of citrus.

For the second time in two decades, the Yuma County Citrus Pest Control District has been successful in eradicating an infestation of California Red Scale in a commercial citrus grove within its boundaries. The first infestation, found in 1973, was declared eradicated in 1980. The latest infestation was found in 1984 and will be eradicated in record time. Eradication can be declared early next year after the third series of three sprayings each.

The influence of 12 different rootstocks on yield and quality of "Redblush" grapefruit was studied for several years. Rootstocks consisted of: macrophylla, volkameriana, rough lemon, Palestine sweet lime, sour orange, Carrizo citrange, taiwanica, Savage citrange, Citrumelo, Ichang pummelo, Troyer citrange and Cleopatra mandarin. Trees on volkameriana, Palestine sweet lime, rough lemon, and sour orange had higher yield than other rootstocks, while trees on Savage citrange had lowest yield. However, soluble solids and acid /sugar ratio were relatively low in the fruits on volkameriana but high in fruit on Savage citrange rootstocks.

Activity under the Arizona Cooperative Citrus Registration- Certification Program was at a new low during 1984 and 1985; no trees were budded under the program during that period. however, increased budding and bud sales during 1986 herald increased activity in the future. Because the program has continued to receive the support of the citrus industry, services have been provided uninterrupted. The program continues to maintain the foundation blocks insuring the industry with sources of budwood that have successfully met all requirements for: 1) freedom from known viruses or virus-like disorders, 2) freedom from injurious pests and diseases, and 3) trueness to horticultural type.

With the high cost of maintaining and operating wind machines, growers are increasingly interested in alternative methods of freeze protection. Several possible frost protectant materials were applied to Valencia oranges at the Yuma Mesa Agricultural Center. Although temperatures reached the mid-to-upper 20s at the test site during the winters of 1984-1985 and 1985-1986, no frost damage occurred. As a result, it was impossible to evaluate the effectiveness of the materials.