Leucoptera Coffeella Research Articles

Plant Extracts as an Alternative to Control Leucoptera coffeella (Guérin-Mèneville) (Lepidoptera: Lyonetiidae)

We evaluated the effects of crude extracts from the plantain Plantago lanceolata and the bitter gourd Momordica charantia on the oviposition preference and development of the coffee leaf miner Leucoptera coffeella Guérin-Mèneville & Perrottet under laboratory and/or greenhouse conditions. The ovicidal effects of these extracts were also studied in a greenhouse. Plantago lanceolata and M. charantia extracts also underwent fractionation directed by oviposition tests with the coffee leaf miner. The extracts of both plants reduced L. coffeella oviposition and egg hatching, apparently as a result of action of plant metabolites on the embryo. Adults originating from eggs treated with the extracts exhibited similar survival rates, but a higher female/male ratio. Fecundity was reduced for females obtained from eggs treated with the M. charantia extract. Partial chemical analysis indicated that both extracts produced polar fractions that reduced the oviposition of L. coffeella on coffee leaves under laboratory conditions. The extracts of P. lanceolata and M. charantia have potential for use in the development of new products to control the coffee leaf miner.

Molecular characterization of a miraculin-like gene differentially expressed during coffee development and coffee leaf miner infestation

The characterization of a coffee gene encoding a protein similar to miraculin-like proteins, which are members of the plant Kunitz serine trypsin inhibitor (STI) family of proteinase inhibitors (PIs), is described. PIs are important proteins in plant defence against insects and in the regulation of proteolysis during plant development. This gene has high identity with the Richadella dulcifica taste-modifying protein miraculin and with the tomato protein LeMir; and was named as CoMir (Coffea miraculin). Structural protein modelling indicated that CoMir had structural similarities with the Kunitz STI proteins, but suggested specific folding structures. CoMir was up-regulated after coffee leaf miner (Leucoptera coffella) oviposition in resistant plants of a progeny derived from crosses between C. racemosa (resistant) and C. arabica (susceptible). Interestingly, this gene was down-regulated during coffee leaf miner herbivory in susceptible plants. CoMir expression was up-regulated after abscisic acid application and wounding stress and was prominent during the early stages of flower and fruit development. In situ hybridization revealed that CoMir transcripts accumulated in the anther tissues that display programmed cell death (tapetum, endothecium and stomium) and in the metaxylem vessels of the petals, stigma and leaves. In addition, the recombinant protein CoMir shows inhibitory activity against trypsin. According to the present results CoMir may act in proteolytic regulation during coffee development and in the defence against L. coffeella. The similarity of CoMir with other Kunitz STI proteins and the role of CoMir in plant development and plant stress are discussed.

Leaf Alkaloids, Phenolics, and Coffee Resistance to the Leaf Miner <I>Leucoptera coffeella</I> (Lepidoptera: Lyonetiidae)

Coffee (Coffea spp.) alkaloids (caffeine and related methylxanthines) and phenolics (caffeic and chlorogenic acids) have recognized pestistatic/pesticidal activity and mediate insect-plant interactions. The present investigation assessed the resistance of 12 coffee genotypes to the leaf miner Leucoptera (= Perileucoptera) coffeella (Guérin-Méneville & Perrottet) (Lepidoptera: Lyonetiidae) and correlated such results with the leaf content of coffee alkaloids and phenolics that probably play a role in the interaction between coffee and this leaf miner. The levels of chlorogenic and caffeic acid, caffeine, and related methylxanthines were measured and quantified in leaf extracts of these genotypes before and 7 d after their infestation by the leaf miner. Some coffee genotypes (Coffea canephora L. and Coffea racemosa Lour. and its hybrids with Coffea arabica L.) exhibited high pesticidal activity (100% mortality) toward the L. coffeella, indicating their antibiosis resistance. However, there was no correlation between this activity and the leaf levels of coffee alkaloids and phenolics. Curiously, infestation by L. coffeella leads to a nearly four-fold decline in the leaf levels of chlorogenic acid, which does not affect this pest species but may affect other generalist species. Indeed, chlorogenic acid sprayed on coffee leaves stimulated locomotory activity of the green scale Coccus viridis (Green) (Hemiptera: Coccidae), thus minimizing their feeding in contrast with the absence of this polyphenol. Therefore, reduction of chlorogenic acid levels in coffee leaves due to leaf miner infestation seems to also favor infestation by generalist insects, such as the green scale.

A diversificação da vegetação reduz o ataque do bicho-mineiro-do-cafeeiro Leucoptera coffeella (Guérin-mèneville) (Lepidoptera: Lyonetiidae)?

The effects of increasing plant diversity on the population of the coffee leaf-miner Leucoptera coffeella (Guérin-Mèneville) were investigated in two organic coffee production systems. One system consisted of coffee intercropped with banana trees (shaded system) and the other one of coffee intercropped with pigeon pea (unshaded system). The increase in plant diversity on both systems was achieved via introduction of green manures such a perennial pea nut, sunn hemp and Brazilian lucerne. The population of L. coffeella, predation and parasitism of L. coffeella mines were biweekly evaluated during eight months. The increase in plant diversity on both systems did not affect the attack of L. coffeella on coffee leaves and the mine parasitism rate. However, there was a positive and significant relationship between increasing plant diversity and coffee leaf mine predation by wasps on unshaded coffee system and a negative relationship on shaded coffee system.

SUPLEMENTOS ALIMENTARES E ISCA TÓXICA NO MANEJO DO BICHO-MINEIRO E DE SEUS INIMIGOS NATURAIS

This work assessed the effect of food supplements on the population of the coffee leaf-miner Leucoptera coffeella (Guerin-Meneville & Perrottet) (Lepidoptera: Lyonetiidae) and its natural enemies. The experiment was set up at the Federal University of Lavras (UFLA) in a five-year-old dense, conventional cv. Rubi crop planted in a 2.0 x 0.6 m spacing. The experimental design was in randomized blocks with six treatments and four replications. The treatments were: beer yeast and honey (1:1) at 20%, molasses at 10%, hydrolyzed protein at 2%, hydrolyzed protein at 2% with cartap (20 g a.i./ha) (toxic bait), cartap (20 g a.i./ha) and control (water). The features assessed were: percentage of mined leaves, percentage of mined leaves preyed on by wasps, number of live coffee leaf-miner caterpillars, number of pupae formed per sixty leaves and the percentage of parasitism. The most important parasitoids were Orgilus niger , Centistidea striata , Stiropius reticulatus and Horismenus sp. After application of the toxic bait and cartap insecticide treatments, a reduction in both the total parasite population and per parasitoid species was observed. The results suggest further studies for recommending food supplements as a pest management tactic in coffee crops. Toxic bait used to manage the coffee leaf-miner affected negatively the population of its natural enemies.

Transformation of coffee (Coffea Arabica L. cv. Catimor) with the cry1ac gene by biolistic, without the use of markers

The transformation of coffee plantlets with the cry1ac gene of Bacillus thuringiensis was achieved by biolistic using either the whole pUBC plasmid or only the ubi-cry1ac-nos genetic cassette. The cry1ac gene was inserted into coffee plants in order to confer resistance to the leaf miner Leucoptera coffeella, an insect responsible for considerable losses in coffee crops. Bearing in mind that the genetic cassettes used for this study lack reporter genes and/or selection marker genes, the parameters for the transformation procedure by biolistic were previously standardised with a plasmid carrying the gus reporter gene. The presence of the cry1ac gene in young plantlet tissues was determined by PCR, Southern blot and reverse transcription-PCR. Our results show that the obtainment of viable coffee plantlets, transformed by bombardment with the cry1ac gene and without selection markers nor reporter genes, is feasible.

Impacts of weather, shade cover and elevation on coffee leafminer Leucoptera coffeella (Lepidoptera: Lyonetiidae) population dynamics and natural enemies

We assessed the influences of ambient temperature, rainfall, shade cover and elevation on seasonal abundance of coffee leafminer Leucoptera coffeella (Guérin-Ménèville) and its natural enemies in coffee farms in the Soconusco region of Chiapas, Mexico. Mined coffee leaves were most abundant during the rainy season (i.e. historical average rainfall >200 mm/mo, April–November) compared to the dry season (<100 mm/mo, December–March), and at low (<600 m asl) relative to high (>900 m asl) elevations. The abundance of mined leaves increased with rainfall, and decreased with maximum daily temperatures. Coffee leafminer survivorship was highest during the dry season (>40%), when predation was lowest (<10%). Predation was the main source of coffee leafminer mortality, and was greatest during the rainy season (>25%) when coffee leafminer incidence was highest (>30% mined leaves per plant). None of the weather variables that were evaluated (viz. maximum and minimum temperatures, and rainfall) significantly impacted parasitism ratios. Shade cover moderated on-farm temperatures, by reducing maximum daily temperatures and any potential, direct impacts of rainfall on coffee leafminer, by providing partial shelter from rainfall, but did not significantly affect coffee leafminer incidence. In 48 h laboratory trials, coffee leafminer oviposition was highest at 28 °C (∼15 eggs/female), minimal at 25 °C (∼3 eggs) and nil at 20 °C, and higher during night-time hours (>8 eggs/female/day) compared to day-time hours (<1 egg). Historical average temperatures were higher at low elevation (yearly average ca. 25 °C; range = 18.0–32.0 °C) than at high elevation (ca. 21 °C; 13.5–28.5 °C), and we predicted that physical environmental conditions (i.e. night-time hours with temperatures > 20 °C) were permissive of coffee leafminer oviposition during twice as many hours each year at low elevation (4060 h) compared to high elevation (2081 h). Overall, our results suggested that evident differences in the abundance of coffee leafminer between elevations may be due in considerable part to differences in ambient temperatures, particularly night-time temperatures, rather than rainfall, shade cover, or elevation per se.

Diversidade de hemerobiídeos (Neuroptera) e suas associações com presas em cafeeiros

O objetivo deste trabalho foi avaliar a diversidade de Hemerobiidae (Neuroptera) em cafeeiros, e suas relações com Leucoptera coffeella, Coccus sp., Planococcus sp., Oligonychus ilicis, Brevipalpus phoenicis, Aphis spiraecola e Toxoptera aurantii. As amostragens foram realizadas em Cravinhos, SP, entre maio de 2005 e abril de 2007. Os hemerobiídeos foram coletados com rede de varredura, armadilha de Möricke e armadilhas luminosas e, para a amostragem das presas, foram coletadas folhas de cafeeiro. Foram obtidos 882 exemplares de hemerobiídeos: Nusalala tessellata (467 espécimes, 52,9% do total coletado), Hemerobius bolivari (153, 17,3%), Megalomus impudicus (114, 12,9%), Sympherobius miranda (109, 12,4%), Megalomus rafaeli (30, 3,4%), Sympherobius ariasi (6, 0,7%) e Nomerobius psychodoides (3, 0,3%). A ocorrência de Nusalala tessellata e M. impudicus foi correlacionada positivamente à de Coccus sp.; o mesmo fato ocorreu para M. rafaeli com lagartas de L. coffeella e A. spiraecola e para H. bolivari com O. ilicis. As correlações foram negativas e significativas entre as ocorrências de S. miranda e O. ilicis e entre as de N. tessellata e L. coffeella e O. ilicis. As correlações mostraram que os Hemerobiidae, predadores generalistas, foram favorecidos pelo constante suprimento de presas que ocorreram na cultura do café, no período estudado.

Geostatistical analysis of the spatial variation of the berry borer and leaf miner in a coffee agroecosystem

The advent of geostatistics and geographical information systems has made it possible to analyze complex spatial patterns of ecological phenomena over large areas in applied insect ecology and pest management. The objective of this study was to use geostatistics to characterize the spatial structure and map the spatial variation of damage caused by the berry borer (Hypothenemus hampei) and leaf miner (Leucoptera coffeella) in a coffee agroecosystem planted with the cultivar Catuai Vermelho IAC-99. Infestations of berry borer and leaf miner were evaluated in fruits and leaves, respectively. The pests were monitored at 67 georeferenced points in an area of 6.6 ha in 2005, 2006 and 2007. Variograms estimated by the method of moments (MoM) and residual maximum likelihood REML were compared. The latter were generally better in terms of the kriging error coefficients. Spherical variograms estimated by REML for berry borer infestation in fruits had ranges of spatial dependence of 34.62–118.4 m and for the leaf miner they were 53.93–133.7 m. For models fitted by weighted ordinary least squares (OLS) to the MoM experimental variogram, the ranges varied between 37.22 and 68.67 m for the berry borer and 100 and 155.4 m for leaf miner infestation. The variogram model parameters were used with the data for ordinary kriging to map the spatial variation of coffee pests for different monitoring periods. If there was no suitable variogram, inverse distance weighting was used to map the variation. The maps enabled visualization of the intensity of infestation of the insect pests for the different periods evaluated.

Chemical Analysis of Female Volatiles and Field Response of the Coffee Leafminer Moth (Lepidoptera: Lyonetiidae) to Stereoisomers of Its Major Sex Pheromone Component

ABSTRACT We analyzed the volatiles emitted by Mexican populations of the female coffee leafminer moth Leucoptera coffeella that were collected in coffee plantations located in the Soconusco region of Chiapas. Our results confirmed previous results that L. coffeella females emitted 5,9-dimethylpentadecane as the major and 5,9-dimethylhexadecane as the minor component. Field response of the coffee leafminer moth to stereoisomers of the major component showed that delta traps baited with (5S,9R)-dimethylpentadecane caught a significantly greater number of coffee leafminer males when compared to those captured by traps baited with (5R,9R)-dimethylpentadecane, (5R,9S)-dimethylpentadecane and the control. The number of coffee leafminer captured by traps baited with (5S,9S)-dimethylpentadecane was not significantly different from the number captured by traps baited with (5R,9R)-dimethylpentadecane. The results are discussed in view of the possibility of using stereoisomers as bait for monitoring the leafminer mo...

Agroforestry management affects coffee pests contingent on season and developmental stage

Abstract1 Management of vegetational diversity in agroecosystems is a potentially regulating factor of pest population dynamics and may affect developmental stages in different ways.2 We investigated the population dynamics of red spider mites, coffee leaf miners, and coffee berry borers in three management types of coffee agroforests: increasing plant diversity from a few shade tree species (simple‐shade agroforests), intermediate‐shade tree species (complex‐shade agroforests) to high‐shade tree species (abandoned coffee agroforests) in Ecuador. Furthermore, we studied how changes in agroforestry management affect population stage structure of each coffee pest.3 Our results show that agroforestry management affected seasonal patterns of coffee pests in that higher densities of red spider mites were observed from August to December, coffee leaf miners from December to February, and coffee berry borers from May to July. Moreover, specific developmental stages of red spider mites, coffee leaf miners, and coffee berry borers differed in their responses to agroforestry management. During all stages, red spider mite reached higher densities in simple‐shade agroforests compared with complex‐shade and abandoned agroforests. Meanwhile, coffee leaf miner densities decreased from simple‐shade to complex‐shade and abandoned agroforests, but only for larvae, not pupae. Similarly, only coffee berry borer adults (but not eggs, larvae and pupae) demonstrated a response to agroforestry management. Environmental variables characterizing each agroforestry type proved to be important drivers of pest population densities in the field.4 We emphasize the importance of considering seasonal differences and population structure while investigating arthropod responses to different habitat types because responses change with time and developmental stages.

Efficacy of Mating Disruption for Control of the Coffee Leaf Miner

The coffee leaf miner, Leucoptera coffeella (Guerin-Meneville) (Lepidoptera: Lyonetiidae), is the main pest of coffee plantations in Brazil. Indiscriminate chemical control has been used frequently to control the attack of L. coffeella, causing serious problems to the environment. To avoid such problems, new techniques have been developed to control the attack of this pest. A technique to control lepidopteran pests, called mating disruption, aims to obstruct the communication among sexual partners. The potential of pheromone-mediated mating disruption for control of leaf miner population was evaluated in a coffee plantation in Patrocinio-MG, Brazil. Three experimental areas were installed: 20 ha plot treated with synthetic sex pheromone; another 20 ha plot with insecticide applications and 20 ha plot maintained as control. The pheromone plot was treated with 400 pheromone dispensers with 1g of 5,9-dimethylpentadecane per dispenser. The efficacy of mating disruption was evaluated by the comparison of number of males caught in delta traps (20 traps per plot) baited with 0.5 mg of 5,9 - dimethylpentadecane. The number of mined leaves was also recorded in each plot. The presence of pheromone did not reduce the number of males caught nor decreased the number of mined leaves in the plot. The failure of the mating disruption technique may be attributed to a combination of several factors, such as composition and dose of the pheromone and its formulation, the moment of application in the crop, the population density at the begin of the experiment and climatic factors.

Seletividade Fisiológica de Inseticidas a Vespas Predadoras (Hymenoptera: Vespidae) de Leucoptera coffeella (Lepidoptera: Lyonetiidae)

Conservation of natural enemies is an important component of integrated pest management. In this work, the selectivity of 11 insecticides used for management of Leucoptera coffeella (Guerin-Meneville) was studied to Protonectarina sylveirae (Saussure), Polybia scutellaris (White) and Protopolybia exigua (Saussure) (Hymenoptera: Vespidae). The insecticides were applied in concentrations corresponding to 50% and 100% of the field rates used for management of L. coffeella. The organophosphates (except to the 50% rate of ethion to P. scutellaris) were highly toxic to all three Vespidae species. Cartap was highly toxic to P. escutellaris and P. exigua but showed median selectivity to P. sylveirae. The pyrethroids cypermethrin, deltamethrin, betacyfluthrin, zetacypermethrin, and esfenvalerate were selective to at least one of wasp species. The mortality of P. scutelaris caused by ethion, cypermethrin, deltamethrin, betacyfluthrin and zetacypermethrin decreased when 50% of the recommended rates were used. This reduction was also observed for the mortality of P. exigua by permethrin and for the mortality of P. sylveirae by deltamethrin. P. sylveirae was the most tolerant species to cartap; P. scutellaris was the most tolerant to ethion, while P. exigua was more tolerant to pyrethroids than P. scutellaris and P. sylveirae. The results of this research indicate that pyrethroid insecticides are likely to be selective to predatory wasps in field settings given their overall selectivity in the conditions of extreme exposure of this study. The possible mechanisms underlying the selectivity of these compounds and the differential tolerance of the wasps are discussed.

Impact of natural enemies on coffee leafminer Leucoptera coffeella (Lepidoptera: Lyonetiidae) population dynamics in Chiapas, Mexico

Coffee leafminer, Leucoptera coffeella, is a pest in many New World coffee growing areas. Previous studies suggested that its population dynamics were strongly affected by natural enemies, particularly of larvae, and physical environmental conditions. Our study documented through field surveys and life table analyses (i) the natural enemy complex associated with coffee leafminer and (ii) the impacts of natural enemies on the population dynamics of coffee leafminer, on coffee ( Coffea arabica) at two elevations and two rainfall levels in the Soconusco region of Chiapas, Mexico. Twenty-two larval parasitoid species (including 14 morphospecies) were collected. Egg and pupal parasitoids were not recovered. Life table analyses showed that parasitism contributed ⩽10% of real mortality, and parasitism rates were 8–10-fold higher at the low (<550 m) versus high (>950 m) elevation; parasitism rates were similar under low (<100 mm) and high (>400 mm) rainfall. Seventeen predator species (including five morphospecies) were collected, of which most were ants (Formicidae, 14 species) that contributed >58% of real mortality. Life table analyses showed that predation rates were higher at high versus low elevation and under high versus low rainfall. Independently of elevation and rainfall, egg predation (likely by ants) was the most important source of indispensable mortality (range = 0.13–0.30), except at low elevation and high rainfall where pupal predation (=0.14) was similarly important. Also, predation was the main source of coffee leafminer larval and pupal mortality during a 13-month period in a low elevation coffee farm and was highest during the rainy season (>400 mm rainfall/month), when coffee leafminer prevalence was highest. Overall, predation of eggs and pupae (the latter particularly at low elevation), mostly by ants, were the most important sources of coffee leafminer mortality. Because ants were the main source of coffee leafminer egg and pupal mortality, their importance and potential role in coffee pest management strategies were discussed.

Efeitos de variáveis ambientais, irrigação e vespas predadoras sobre Leucoptera coffeella (Guérin-Méneville) (Lepidoptera: Lyonetiidae) no cafeeiro

The population density of the coffee leaf miner Leucoptera coffeella (Guérin-Méneville) can be affected by environmental variables in irrigated agroecosystems and the occurrence of predatory wasps such as Vespidae. In here, we aimed to evaluate the effects of environmental variables, drip irrigation depths and predation by wasps on the population density of L. coffeella. The experiment was carried out during 2004 and 2005 in a Coffea arabica plantation cultivated in the county of Jaboticatubas, Minas Gerais State, Brazil. The different irrigation depths set through drip were established considering the daily depth required by the IRRIPLUS program, which was equal to 100%, and two other lower (51% and 72%) and higher (124% and 145%) values, having the control without irrigation. In order to evaluate the coffee leaf miner population density and predation, the number of active and preyed mines was determined on the fourth pair of leaves in a group of ten plants. For the study of interactions among the environmental variables, irrigation depths with the mine density of L. coffeella and predatory wasps, the following methods were used: multivariated analysis, simple linear regression and trail. We concluded that higher pluvial precipitation, solar radiation and irrigation depths would reduce population density of the coffee leaf miner. Furthermore, the increase in density of the predatory wasps was dependent on the population level of L. coffeella.

From the laboratory to the field: contrasting effects of multi‐trophic interactions and agroforestry management on coffee pest densities

AbstractOnly few factors influencing pest populations can be studied in the laboratory, but many population‐driving factors interact in the field. Therefore, complementary laboratory and field approaches are required for reliable predictions of real‐world patterns and processes. Laboratory and field experiments with the red spider mite, Oligonychus ilicis McGregor (Acari: Tetranychidae), and the coffee leaf miner, Leucoptera coffeella Guérin‐Méneville (Lepidoptera: Lyonetiidae), on coffee plants, Coffea arabica L. (Rubiaceae), were combined to study the relative importance of biotic interactions, including resource preferences and natural‐enemy impact, and habitat factors, such as agroforestry type and management intensity, on coffee pest densities. In the laboratory, leaf discs cut from undamaged coffee plants were significantly preferred by red spider mites over those from plants infested with conspecific mites, leaf rust pathogens [Hemileia vastatrix Berkeley &amp; Broome (Uredinales)], or coffee leaf miners, resulting in higher reproductive success. Similarly, undamaged plants were preferred by coffee leaf miners over red spider mite‐infested plants. However, in the field, red spider mite densities were positively correlated with coffee leaf miner and leaf rust densities, thereby contrasting with laboratory predictions. Hence, our study suggests that the importance of resource preferences and fitness expected based on laboratory experiments was suppressed by environmental conditions in the field, though other unassessed biotic interactions could also have played a role. Furthermore, intensified agroforestry was characterized by higher red spider mite densities, whereas densities of its major natural enemy, the predatory mite Amblyseius herbicolus Chant (Acari: Phytoseiidae), were not related to agroforestry management. Densities of coffee leaf miner and its main natural enemy, a eulophid parasitoid (Hymenoptera), were not affected by management practices. In conclusion, patterns found in the laboratory did not hold for the field, emphasizing the difficulties of extrapolating small‐scale experiments to larger spatial scales and the need to combine both approaches.

The leaf-miner (Leucoptera coffeella) incidence in coffee culture (Coffea arabica) under central pivot irrigation.

The leaf-miner (LM) [ Leucoptera coffeella (Guerin-Meneville & Perrottet, 1842) (Lepidoptera: Lyonetiidae)] is one of the most powerful parasites for the coffee plants ( Coffea arabica L.), being responsible for high economic losses to coffee farmers. In the last years, the adoption of irrigation systems has been becoming a common practice in Brazilian coffee farms, mainly center pivot irrigation. The principal factors that contribute to the increase of irrigated fields are the negative effects of bad rain distribution and hydric scarceness. However, there is data describing the behavior of this parasite in irrigated crops. The aim of this work was to verify the incidence of LM in a coffee fields submitted to a center pivot irrigation system with different water depths applied. The research was carried out in a experimental field with total area of 1,6 ha located in the Engineering Department of the Federal University of Lavras. The coffee trees susceptible to LM were planted in 1999, each plot with 3,5m x 0,8m of space between plants. The work was designed in randomized block model and treatments analyzed were 6 water depths applied (0, 60, 80, 100, 120 and 140% of evaporation of the class A tank - ECA) in different periods of evaluation, in a factorial scheme (6 x 12) with 3 repetitions. The LM infection in the plants was verified by visual evaluation of leaf damages caused by the parasite. The analyses were proceeded in intervals of 23 days, from April of 2004 to March of 2006. Each experimental group was composed of eight plants. Ten plagiotropics branchs were sampled in the medium part of tree, being five of the south and five of the north side of the plant. Two leaves located in the thrith or fourth pair of each branch was collected, in total of 160 leaves per experimental group. The mean dates of percentage of mined leaves were transformed using the formula (X + 0,5) 1/2 and an analysis of variance was made. The results showed a significant interaction between water depths and LM incidence. The higher incidence of LM infection was observed in no irrigated plants. The experimental group submitted 140% ECA showed lower LM parasitism. The higher amount of the insects was observed in the north side of plants. Two peaks of LM incidence occurred, in January and July, with high number in the first.

Enzimas digestivas do bicho-mineiro do cafeeiro Leucoptera coffeella (Guérin-Mèneville &amp; Perrottet, 1842) (Lepidoptera: Lyonetiidae)

Os insetos possuem diferentes enzimas digestivas que catalisam as reações de hidrólise do alimento consumido e essas se diferenciam entre os insetos de acordo com suas dietas e estado fisiológico. Foram avaliadas as atividades de algumas enzimas digestivas da praga do cafeeiro - Leucoptera coffeella (Guérin-Mèneville &amp; Perrottet, 1842) (Lepidoptera: Lyonetiidae) - popularmente conhecida como bicho-mineiro do cafeeiro, para o entendimento de seu processo digestivo. Lagartas do bicho-mineiro do cafeeiro foram coletadas em campo e em casa-de-vegetação. O extrato enzimático utilizado foi obtido pela maceração das lagartas em água (4ºC). Determinaram-se os pH's ótimos e as atividades das enzimas α e β-glicosidases, α-amilase, aminopeptidase, fosfatase alcalina, sacarase, trealase e tripsina, incubando o extrato enzimático do bicho-mineiro do cafeeiro com substratos específicos. A análise dos resultados sugere que o processo digestivo e o ambiente intestinal do bicho-mineiro do cafeeiro sejam similares com o dos demais lepidópteros encontrados na literatura.

Arboreal Ant Abundance and Leaf Miner Damage in Coffee Agroecosystems in Mexico

ABSTRACTShaded coffee agroecosystems traditionally have few pest problems potentially due to higher abundance and diversity of predators of herbivores. However, with coffee intensification (e.g., shade tree removal or pruning), some pest problems increase. For example, coffee leaf miner outbreaks have been linked to more intensive management and increased use of agrochemicals. Parasitic wasps control the coffee leaf miner, but few studies have examined the role of predators, such as ants, that are abundant and diverse in coffee plantations. Here, we examine linkages between arboreal ant communities and coffee leaf miner incidence in a coffee plantation in Mexico. We examined relationships between incidence and severity of leaf miner attack and: (1) variation in canopy cover, tree density, tree diversity, and relative abundance of Inga spp. shade trees; (2) presence of Azteca instabilis, an arboreal canopy dominant ant; and (3) the number of arboreal twig‐nesting ant species and nests in coffee plants. Differences in vegetation characteristics in study plots did not correlate with leaf miner damage perhaps because environmental factors act on pest populations at a larger spatial scale. Further, presence of A. instabilis did not influence presence or severity of leaf miner damage. The proportion of leaves with leaf miner damage was significantly lower where abundance of twig‐nesting ants was higher but not where twig‐nesting ant richness was higher. These results indicate that abundance of twig‐nesting ants in shaded coffee plantations may contribute to maintenance of low leaf miner populations and that ants provide important ecosystem services in coffee agroecosystems.

Effect of coffee alkaloids and phenolics on egg-laying by the coffee leaf miner Leucoptera coffeella

The recognized importance of coffee alkaloids and phenolics mediating insect-plant interactions led to the present investigation aiming to test the hypothesis that the phenolics chlorogenic and caffeic acids and the alkaloid caffeine and some of its derivatives present in coffee leaves affect egg-laying by the coffee leaf miner Leucoptera (=Perileucoptera) coffeella (Guérin-Méneville & Perrottet) (Lepidoptera: Lyonetiidae), one of the main coffee pests in the Neotropical region. These phytochemicals were, therefore, quantified in leaves from 12 coffee genotypes and their effect on the egg-laying preference by the coffee leaf miner was assessed. Canonical variate analysis and partial canonical correlation provided evidence that increased leaf levels of caffeine favour egg-laying by the coffee leaf miner. An egg-laying preference bioassay was, therefore, carried out to specifically test this hypothesis using increasing caffeine concentrations sprayed on leaves of one of the coffee genotypes with the lowest level of this compound (i.e. Hybrid UFV 557-04 generated from a cross between Coffea racemosa Lour. and C. arabica L.). The results obtained allowed the recognition of a significant concentration-response relationship, providing support for the hypothesis that caffeine stimulates egg-laying by the coffee leaf miner in coffee leaves.