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Peach cultivars are being evaluated for their adaptation to the conditions of the central region of Puerto Rico. The root weevil, Diaprepes abbreviatus (L.), a common insect pest in the area, is being previously reported on peach trees. With the purpose of evaluating the potential feeding damage that this insect might represent for future peach production, choice and no-choice tests were made with leaf discs (feeding) and leaf strips (oviposition) to determine adult feeding and oviposition behavior in comparison with `Navel' orange. Larval feeding behavior on the roots was studied on a peach rootstock and `Cleopatra' mandarin planted in 18.9-L containers. In the no-choice test, adults fed significantly more on `Navel' orange foliage than on peach foliage. In the choice test, adults preferred to feed on `Navel' orange leaf discs. Oviposition occurred on both peach cultivars tested, but more egg masses were laid on Navel orange leaf strips in the no-choice test. However, given the choice, adults preferred to oviposit on peach leaf strips while fed on `Navel' orange leaf strips. In some replications this behavior was reversed. At 90 days after infestation, larval feeding damage on the roots was severe on `Cleopatra' mandarin where most of the cortex tissue on the primary root was removed and growth of roots and foliage was reduced. Larvae bore also on peach trees, but there was no sign of growth reduction on foliage or the roots compared to the control. These preliminary results indicate that D. abbreviatus will not be a primary pest on peach.
Abstract
Foam was applied for frost protection to January planted cantaloupes (Cucumis melo L.) in the Lower Rio Grande Valley of Texas. Two planting configurations consisting of shallow trenches and conventional beds were compared to evaluate volume of foam required and durability. The trench planting technique increased the foam’s durability and reduced the volume approximately three-fourths. The cost of foam application to a low profile crop in the shallow trenches was approximately $74.00 per hectare. Leaf temperature in the foamed trenches was up to 12°C warmer than nonfoamed conventional beds.
Screening for resistance to mixed infections with pepper huasteco virus (PHV) and pepper golden mosaic virus (PepGMV) was carried out on plants representing wild pepper accessions collected in different states of México. One accession collected in Yucatán (BG-3821) corresponded to Capsicum chinense Jacq., and three collected from Michoacán (BG-3818), Tamaulipas (BG-3820), and Sinaloa (BG-3819) were identified as C. annuum L. Forty-eight plants were initially inoculated with a 1:1 mix of PHV and PepGMV DNAs by a biolistic method. Those plants that did not show typical symptoms after the biolistic method, were inoculated by grafting. Half of the plants (24) were highly susceptible, while the other half expressed different degrees of resistance. Of the resistant individuals, eight plants were asymptomatic and viral DNA of both viruses was detected in low levels. Two individuals showed delayed symptoms 34 days after symptom expression in the control plants. This delay was correlated with an increase in PHV DNA levels when plants became symptomatic. The remaining 14 plants showed symptom remission in newly developed leaves at 31 days postinoculation, and this asymptomatic effect was correlated diminished PHV DNA within the plants. Our results suggest that the resistance shown by some individuals to geminivirus mixed infections (PHV and PepGMV) is likely due to constrains in viral movement.