Chilling requirements and maturity of several varieties of peaches and apples were studied at the University of Arizona, Yuma Mesa Agricultural Center (Southwest Arizona) in 1985-1986. Flordared, Flordabelle, Flordabeauty, Flordagold, Desert Gold and Suwanee peaches broke their dormancy earlier than other cultivars and showed full bloom between mid-to-late January. Suwanee and Desert Gold matured earlier than other tested varieties, but they produced small size fruit with low sugar content. Anna and Dorsett Golden apples showed extended blooming period due to insufficient chilling.

Sodium tetrathiocarbonate (STTC) releases carbon disulfide when added to water and applied to soil. Laboratory tests were conducted to determine the effect of this chemical on growth and sporulation of Phytophthora citrophthora and P. parasitica, which cause Phytophthora gummosis and mot rot of citrus in Arizona Zoospore motility, zoospore cyst viability, sporangia production, and mycelia' growth were significantly reduced in the presence of STTC Results of laboratory tests suggest that application of S7TC as a soil drench could reduce inoculum production and subsequent new infections by P. citrophthora and P. parasitica.

Initial studies of Fuller rose beetle (FRB) biology have found some adult emergence in late June and early July. No adults woe found in foliage in May or early June, nor was activity noted in August and early September. FRB were not found in early October, but they began expected major emergence in mid-October. Several FRB collected did not have fused wings, atypical for this species. This finding suggests flight ability in FRB, currently unknown to occur.

Two rates of Avermectin were mound- applied; one treatment of Avermectin B one of Carzol were applied by air to citrus in April for control of citrus thrips. Plots were sampled by beating new terminal growth and counting thrips. Ground applications had fewer thrips than applications made by air. Avermectin B1 treatments had significantly fewer thrips than Carzol at all sample dates.

No description available.

During the last 15 years, the Yuma County Citrus Pest Control District (YCCPCD) has twice eradicated infestations of California Red Scale within the district. A third infestation, found in late 1984 is currently being fought with eradication as the goal.

Effects of 12 rootstocks on yield, yield efficiency, bearing potential and quality of 'Redblush' grapefruit were measured and potential rootstocks recommended for the arid climate of southwest Arizona. Trees on 'Palestine' sweet lime and 'Volkamer' lemon produced high cumulative yield but small fruit. Trees on Macrophylla (Alemow) produced higher yields after 5 years of planting and had significantly higher mean yield efficiency than trees on other rootstocks. Thus, Macrophylla rootstock could be a good choice for 'Redblush' at the standard spacing and perhaps at high density spacing in southwest Arizona. Fruit of trees on 'Carrizo' and 'Troyer' citranges were largest. Trees on 'Savage' citrange had lowest yield thinnest peel and highest levels of total soluble solids and soluble solids /acid ratio. Fruit of trees on 'Swingle' citrumelo or C.P.B. 4475 rootstock consistently had higher percentage acid than those on other rootstocks. Considering yield and /or various quality factors, 'Volkamer' lemon, rough lemon , 'Palestine' sweet lime, 'Oklawaha' sour orange and particularly 'Carrizo' citrange are suitable for 'Redblush' grapefruit in the arid Southwest. 'Savage' citrange, 'Ichang' pummelo , 'Cleopatra' mandarin, and 'Swingle' were poor yielding rootstocks for 'Redblush ' grapefruit, and therefore undesirable for planting under the standard spacing of this experiment. 'Savage' and 'Swingle' might be good choices at higher densities because they have yield efficiency, high maximum bearing potential and quality.

Long term comparisons of 8 types of lemons (Citrus limon Bunn. F.) on Macrophylla (Alemow) (C. macrophylla) rootstock regarding yield, tree growth, and quality under the arid conditions of the Southwest were studied. 'Foothill Lisbon' showed significantly higher cumulative yield and total acid than 'Monroe Lisbon', 'Prior Lisbon', Eureka strains, and Villa Franca, and had larger fruit than other Lisbon strains. 'Prior Lisbon' produced larger tree canopy than all other strains. Overall, Eureka strains and 'Villa Franca' had lower relative cumulative yield, yield efficiency, canopy volume, soluble solids, total acid and fruit seed content , but higher soluble solids to acid ratio than Lisbon strains. All factors considered 'Foothill Lisbon' and 'Prior Lisbon' have good potential for planting in the arid climate and sandy soil of Southwest, when Macrophylla rootstock is to be used.

Interest in growing blood oranges in Arizona has been increasing in recent years, especially for producing fruit for sale in roadside stands. The Arizona Cooperative Citrus Registration Certification Program now has four selections from which to choose: 'Moro', 'Tarocco', 'Sanguinelli', and 'Ruby'. Each one has distinct advantages and disadvantages that should be considered before making a selection.

A variety of insecticides have been tested during the last three years to keep pace with the ever-present demand for effective materials to control mites and thrips on citrus. This need is particularly acute with the recent loss of dicofol (Kelthane), which for years was an industry standard for mite control. Some of the more promising new compounds include Avermectin and NC 21314. Comments are included concerning the registration status of some of the compounds we tested. Cautions are given concerning the development of resistance to compounds which are soon to be available.