Spatial distribution of Phyllocnistis citrella Station (Lepidoptera: Gracillariidae) larvae in three scales (original) (raw)
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Brazilian Journal of Biology, 2008
The spatial distribution of larvae of Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae), the citrus leaf miner, in leaves, shoots, and tree crowns of Montenegrina tangerine (Citrus deliciosa Tenore) and Murcott tangor (Citrus sinensis L. Osbeck x Citrus reticulata Blanco) was determined. Fortnightly samplings from July/2001 to June/2003, in orchards located in Montenegro (29º 68 S and 51º 46 W), RS, Brazil, were carried out. At each sampling occasion eighth shoots randomly selected were collected. The spatial distribution pattern of P. citrella larvae between tree crowns and in the shoots was aggregated in most sampling occasions in both citrus species. Nevertheless, on the leaves, this pattern followed a random distribution, as indicated by the indices I, Id and k parameter.
Menoufia Journal of Plant Protection, 2016
Selected citrus trees represented three varieties (noval orange , sweet orange and mandarin). The aim of this study was to monitor population fluctuation of citrus leaf-miner, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae) on noval orange, sweet orange and mandarin , as well as to know the effect of air temperature , relative humidity and dew point on population fluctuation of larvae. The obtained results revealed that number of P. citrella larvae /leaf were more on noval orange than sweet orange and mandarin trees. Phyllocnistis citrella populations increased during summer months and declined during fall and winter. During the study period, 4-5 peaks of pest populations recorded on the summer shoots and 1 peak on the fall and winter shoots. Statistical analysis of the obtained data show that there are positive correlation between population of P. citrella and each of temperature, relative humidity and dew point.
Brazilian Journal of Biology, 2008
Many species of microhymenopterous parasitoids have been registered on Phyllocnistis citrella, the citrus leafminer. The present study aimed to identify the spatial distribution pattern of the native and introduced parasitoids of P. citrella in two citrus orchards in Montenegro, RS. The new shoots from 24 randomly selected trees in each orchard were inspected at the bottom (0-1.5 m) and top (1.5-2.5 m) stratum and had their position relative to the quadrants (North, South, East and West) registered at every 15 days from July/2002 to June/2003. The leaves with pupae were collected and kept isolated until the emergence of parasitoids or of the leaf miner; so, the sampling was biased towards parasitoids that emerge in the host pupal phase. The horizontal spatial distribution was evaluated testing the fitness of data to the Poisson and negative binomial distributions. In Montenegrina, there was no significant difference in the number of parasitoids and in the mean number of pupae found in the top and bottom strata (χ 2 = 0.66; df = 1; P > 0.05) (χ 2 = 0.27; df =1; P > 0.05), respectively. In relation to the quadrants, the highest average numbers of the leafminer pupae and of parasitoids were registered at the East quadrant (χ 2 = 11.81; df = 3; P < 0.05), (χ 2 = 10.36; df = 3; P < 0.05). In the Murcott orchard, a higher number of parasitoids was found at the top stratum (63.5%) (χ 2 = 7.24; df =1 P < 0.05), the same occurring with the average number of P. citrella pupae (62.9%) (χ 2 = 6.66; df = 1; P < 0.05). The highest number of parasitoids and of miners was registered at the North quadrant (χ 2 = 19. 29; df = 3; P < 0.05), (χ 2 = 4.39; df = 3; P < 0.05). In both orchards, there was no difference between the numbers of shoots either relative to the strata as well as to the quadrants. As the number of shoots did not varied much relative to the quadrants, it is possible that the higher number of miners and parasitoids in the East and West quadrants would be influenced by the higher solar exposure of these quadrants. The data of the horizontal spatial distribution of the parasitism fit to the negative binomial distribution in all sampling occasions, indicating an aggregated pattern.
2014
The citrus leaf miner (CLM), Phyllocnistis citrella Stainton (Lepidptera: Gracillariidae), is a potentially serious pest of citrus (oranges, mandarins, lemons, limes, grapefruit and other varieties) and related Rutaceae (kumquat and calamondin) and ornamen tal plants almost worldwide. Several other hosts (Leguminaceae, Lauraceae, Oleaceae etc.) have been reported for CLM, however larvae do not complete their life cycle on these incompatible hosts. CLM is a widespread Asian species, first described from Calcu tta, India. It has been a widely distributed major pest in citrus - growing regions of Asia for many years. In the last 20 years, leaf miners have invaded most of the citrus - producing regions of the world, including the Mediterranean Basin and North, Central , and South America. The citrus leaf miner larvae only infest the younger, flushing foliage causing damage in nurseries and new plantings because of which the growth of young trees is retarded. The pest damage has shown a ...
The citrus leaf miner (CLM), Phyllocnistis citrella Stainton (Lepidptera: Gracillariidae), is a potentially serious pest of citrus (oranges, mandarins, lemons, limes, grapefruit and other varieties) and related Rutaceae (kumquat and calamondin) and ornamen tal plants almost worldwide. Several other hosts (Leguminaceae, Lauraceae, Oleaceae etc.) have been reported for CLM, however larvae do not complete their life cycle on these incompatible hosts. CLM is a widespread Asian species, first described from Calcu tta, India. It has been a widely distributed major pest in citrus - growing regions of Asia for many years. In the last 20 years, leaf miners have invaded most of the citrus - producing regions of the world, including the Mediterranean Basin and North, Central , and South America. The citrus leaf miner larvae only infest the younger, flushing foliage causing damage in nurseries and new plantings because of which the growth of young trees is retarded. The pest damage has shown a 50% increase in citrus canker in o rchards infested with CLM. The total generation period of CLM fluctuates between 13 - 52 days with 2 - 10 days for egg hatching, 5 - 20 days of larval period and 6 - 22 days of pupal development and a temperature of 30°C is optimal for CLM development. Depending o n foliage flushing cycles and weather conditions 6 to 13 generations per year can be expected. Peak pest activity was noticed during September to November months. In the management of this pest chemical control and b iological control are the two key tools . The complex of natural enemies attacking CLM include ants, spiders, small parasitic wasps and predators such as lacewings cau sing up to 90 percent mortality of larvae and pupae . Three of the most effective wasps are Ageniaspis citricola and Cirrospilus quadristriatus and Semiolacher petiolatus. The parasitisation rate was lower in June and July, being higher from August onwards and highest during September month. Unfortunately, the "best" natural enemy may not be found until all natural enemies and their biologies are known. Effective chemical control of CLM is difficult because the larva is protected by leaf cuticle and the pupa is protected by rolled leaf margins. However many pesticides belonging to different chemical groups were tested and found effec tive in its management. Several reports indicated that, the foliar application provides control for two weeks. Several bio - rational pesticides were tested and found useful in CLM management. The biology and management methods were reviewed in detail in thi s paper.
Applied Entomology and Zoology, 2004
Seasonal abundance and parasitism of the citrus leafminer, Phyllocnistis citrella Stainton were investigated in controlled and uncontrolled citrus groves from June 2001 through May 2002 on Citrus iyo (iyotangor) in Ehime Prefecture. No significant difference in mean monthly frequency of P. citrella infestation and its parasitoids was found between controlled and uncontrolled groves. There were two peaks of P. citrella infestation, in July and October. These peaks were strongly related to favorable temperature for P. citrella development and continuous flushing of new shoots. At least seven species of the parasite wasps of P. citrella were observed, of which Chrysocharis pentheus (Walker) and Sympiesis striatipes (Ashmead) were the predominant species. The population drastically increased from July to August, and also from October to November, which coincided with heavy infestation of P. citrella in the iyotangor grove. In spite of a high percentage of parasitism (about 70%) in summer and autumn, the damage to tender leaves was noticeable, because all native parasitoids attacked mature larvae and pupae of P. citrella after they had nearly completed their feeding period.