(D10) PUMMELO: Citrus grandis Osbeck, 'Chandler' PUMMELO-GRAPEFRUIT HYBRID: Citrus grandis Osbeck x paradisi Macf., 'Melogold' Elizabeth E. Grafton-Cardwell Department of Entomology, University of California, Riverside, CA 92521 Phone: (559) 646-6591 Fax: (559) 646-6593 E-mail: email@example.com Christopher A. Reagan Citrus peelminer (CPM): Marmara gulosa Guillen and Davis Two field trials were conducted to test the efficacy of insecticides for the control of citrus peelminer (CPM). The first trial was conducted in an orchard of 'Chandler' pummelos near Exeter, California. The efficacy of multiple applications of an insect growth regulator (Micromite) combined with narrow range spray oil (0.5% v/v) as a surfactant was tested by comparing results of one, two, or three treatments of Micromite. Treatments were assigned based on the pretreatment percentages of fruit with CPM mining activity. Data was collected from three replicated plots per treatment that were four rows wide (approximately 0.7 acres). All fruit within two meters of ground level was examined on five trees in the center rows of each plot. Spray applications of Micromite diluted in 600 gpa began on 6 Jul 2003 using an air blast sprayer (Air-O- Fan D240). Additional treatments were applied approximately three to four weeks apart (29 Jul and 20 Aug). The number of mined fruit and the percentage of the surface area mined for each infested fruit in treated trees were compared to untreated trees. In the second trial, an orchard of 'Melogold' grapefruit near Exeter, California was treated with Success alone, Success followed by Esteem, and Success followed by Esteem then by Success. Narrow range oil (0.5% v/v) was added as a surfactant to all treatments. Each treatment had four replicated plots that were eight rows wide (approximately 1.2 acres) and all fruit within two meters of ground level were examined for CPM mining activity on four trees in the center rows of each plot. The level of CPM mining activity was used to establish treatment locations. Treatments were initiated using an air blast sprayer (Air-O-Fan D240) on 21 Jul, 2003. All sprays were diluted in 300 gpa. Additional sprays were applied at approximately 2-wk intervals, (5 Aug and 18 Aug). The number of fruit with mining activity and the surface area damaged were measured. The percentage of fruit infested with CPM and the percentage of fruit with > 25% surface area mined were analyzed using ANOVA after arcsine transformation and the means were separated according to LSD (P £ 0.05). In the first trial, the percentage of fruit infested with citrus peelminer was significantly lower for treatments of Micromite applied two and three times (Table 1). In addition, the percentage of fruit that was heavily infested (>25% of the surface area of the fruit mined) was reduced for all treatments, but was reduced below 1% for fruit treated multiple times with Micromite (Table 2). Reduction in surface area mined is important for citrus, since small mines may not be cause for downgrading for some citrus varieties in the packinghouse after washing and waxing. In the second trial, the percentage of grapefruit mined by CPM (Table 3) and the percentage of fruit with >25% of the surface area mined (Table 4) were significantly reduced when treated with the sequence of Success, Esteem, and Success over a 4 wk period. These data suggest that multiple treatments are required to reduce CPM damage.
Arthropod Management Tests – Oxford University Press
Published: Jan 1, 2004