Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae) and its relationship with the citrus canker bacterium Xanthomonas axonopodis pv citri in Brazil

Abstract

Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae) e Sua Relação com a Bactéria do Cancro Cítrico Xanthomonas axonopodis pv citri no Brasil RESUMO -Estudou-se em laboratório (28±2ºC, 70±10% UR e fotofase de 14h) e em casa-de-vegetação a relação entre as lesões provocadas pelo ataque do minador-dos-citros, Phyllocnistis citrella Stainton, e a infecção causada pela bactéria do cancro cítrico Xanthomonas axonopodis pv citri. Utilizaram-se, como hospedeiro do minador, plantas de laranja caipira cultivadas em tubetes. Folhas inoculadas com lagartas de segundo e terceiro ínstares ou pupas apresentaram índices de infecção bacteriana de 94,3, 98,3 e 100%, respectivamente. A taxa de infecção foliar por X. axonopodis pv citri em folhas lesionadas pelo inseto foi semelhante àquela observada em folhas danificadas mecanicamente e inoculadas posteriormente com bactéria (94,1 a 97% de pústulas bacterianas). A bactéria penetra também através dos estômatos. Aos sete dias após a inoculação, constatou-se uma taxa de infecção 11 vezes menor nas folhas que não foram lesionadas pelo inseto. O percentual de folhas com cancro aumentou aos 14 dias para 41,2%; esse valor é cerca de 50% menor se comparado às folhas que foram atacadas pelo inseto. Ficou demonstrada a importância dos danos provocados pelo minador-dos-citros no aumento do cancro cítrico, uma vez que as condições favoráveis de temperatura e umidade relativa no interior das minas construídas pelas lagartas, contribuem para um melhor desenvolvimento da bactéria.PALAVRAS-CHAVE: Insecta, praga, minador-dos-citros, doença bacteriana, vetor.ABSTRACT -The relationship of the citrus canker bacterium Xanthomonas axonopodis pv citri with the citrus leafminer (CLM), Phyllocnistis citrella Stainton was investigated. The experiment was conducted under laboratory conditions at 28±2ºC, 70±10% RH and 14h photophase and in a greenhouse. Sweet orange (Citrus sinensis L. Osbeck) "Caipira"cv was used to rear CLM. Plants inoculated with 2 nd and 3 rd instar larvae or pupae showed high percentages (94.3, 98.3 and 100%, respectively) of bacteriuminfected leaves. The damage caused by this insect was responsible for the increase in citrus canker infestation. The leaf infection rate by X. axonopodis pv citri on pre-injured leaves was similar to that observed on mechanically damaged leaves inoculated with the bacterium, with 94.1% to 97.0% of the leaves presenting bacterial pustules. The bacterium can also penetrate through the stomata. An 11-fold lower infection rate was observed as compared to the leaves injured by the insect seven days after inoculation. Under such conditions the percentage of cankered leaves increased to 41.2% at 14 days, a value corresponding to about 50% of the leaves attacked by the insect. In this paper it is also pointed out the significance of the damages caused by CLM in terms of the increase of citrus canker, since the favorable microclimatic conditions of temperature and relative humidity inside the mines built by the larvae account for an improved development o...

Field Evaluation of Integrated Pest Management-Compatible Pesticides for the Citrus LeafminerPhyllocnistis citrella(Lepidoptera: Gracillariidae) and its ParasitoidAgeniaspis citricola(Hymenoptera: Encyrtidae)

“…A connection between insect damage and disease was later described and characterized by Chagas et al (2001) and Jesus Jr. et al (2006). It is assumed that the CLM introduction effectively completed the pathosystem, causing changes in the epidemiology and spatial distribution of citrus canker.…”

“…In addition to the direct damage, the presence of the CLM may facilitate the incidence and increase the severity of citrus canker, a disease caused by the bacterium Xanthomonas citri subsp. citri (Xanthomonadales: Xanthomonadaceae) (Chagas et al 2001;Jesus Jr. et al 2006;Hall et al 2010).…”

Towards the identification and synthesis of the sex pheromone of the citrus leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae)

“…throughout the world. Caterpillar feeding affects not only photosynthesis and development of young plants (Badawy 1967, Heppner 1993, Peña & Duncan 1993, but also opens the door for the citrus canker-causing bacterium, Xanthomonuas axonopodis pv citri (Venkateswarlu & Ramapandu 1992, Cook 1988, Chagas et al 2001) and other pathogens. P. citrella was originally described from Calcutta, India and is now established in five continents (Heppner 1993, Argov & Rössler 1996, Prates et al 1996.…”

Spatial distribution of Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae) larvae in three scales

“…Indirectly, the chief damage caused by P. citrella facilitates the entrance of the bacteria Xanthomonas axonopodis pv. citri (Hasse) Vauterin et al, the causal agent of the citric canker (Chagas et al, 2001;Amaral, 2003). This disease is responsible for serious economic losses because fruit spoilage depreciates its commercial value.…”