Increasing coffee berry borer (Coleoptera: Curculionidae: Scolytinae) female density in artificial diet decreases fecundity

Three experiments were conducted to determine the influence of number of coffee berry borer, Hypothenemus hampei (Ferrari) (Coleoptera: Curculionidae: Scolytinae), females (one, two, or five) reared in artificial diet on fecundity and subsequent development of larvae, pupae, and adults. Our results demonstrated that increasing female density from one to two or five individuals did not result in the expected two- or five-fold increase in progeny, despite ample food resources available. Instead, decreased fecundity was observed with increasing density for all experiments. The mechanism reducing fecundity was not identified, but possibly, volatiles are being produced (e.g., host-marking pheromones). The decrease in fecundity may explain why infestations of only one colonizing female per berry are the norm in the field.     

Increased pathogenicity against coffee berry borer, Hypothenemus hampei (Coleoptera: Curculionidae) by Metarhizium anisopliae expressing the scorpion toxin (AaIT) gene

Coffee berry borer (CBB) is the Worlds most devastating coffee pest causing an estimated US$500 million worth of losses annually through damage and control costs. Beauveria bassiana and Metarhizium anisopliae have been employed to control this pest but their low virulence (slow kill and large inoculums) is an important factor constraining their use. M. anisopliae (AaIT-Ma549) has been modified to express the scorpion toxin (AaIT) in insect hemolymph and this greatly increased pathogenicity against Manduca sexta and Aedes aegypti. Here, we demonstrate that AaIT-Ma549 was also dramatically more virulent against CBB, and we provide a much more comprehensive analysis of infection processes and post-mortality development than in the previous research. We evaluated several spore concentrations (10¹ through 10⁷ spores/ml) of both the wild type and recombinant strain. At concentrations of 10¹, 10² and 10³ spores/ml, the recombinant strain significantly increased mortality of CBB by 32.2%, 56.6% and 24.6%, respectively. The medial lethal concentration (LC₅₀) was reduced 15.7-fold and the average survival time (AST) was reduced by 20.1% to 2.98 ± 0.1 days with 10⁷ spores/ml. This is the first occasion that an entomopathogenic fungus has been found to kill CBB in less than 3 days. However, AaIT-Ma549 produces significantly fewer spores on cadavers than the parental strain.     

Biological control of the coffee berry borer Hypothenemus hampei (Coleoptera: Curculionidae) by Phymastichus coffea (Hymenoptera: Eulophidae) in Colombia

The potential of the eulophid parasitoid Phymastichus coffea LaSalle to control coffee berry borer Hypothenemus hampei (Ferrari) populations under field conditions in Colombia was evaluated. Parasitoid adults were released one, five and nine days after artificial infestations of 90-, 150- and 210-day-old coffee berries with H. hampei females. The position of the beetle inside the berry and the parasitism levels were assessed ten days after each P. coffea release. Parasitism of H. hampei by P. coffea was significantly affected by the age of the berries at the time of infestation, and by the position of the beetle inside the berries. Highest levels of parasitism were recorded in 150-day-old berries (75-85%) and in 90-day-old berries (75%) when P. coffea were released one day after the artificial infestation with H. hampei. In 150-day-old berries, highest levels of parasitism were recorded for H. hampei found in the outer layer of the endosperm followed by beetles penetrating the exocarp. Increasing the time of P. coffea releases after the artificial infestations with H. hampei led to decreased levels of parasitism in beetles attacking 90- and 150-day-old coffee berries. Low levels of parasitism were recorded in H. hampei females infesting older coffee berries because most of the beetles had already constructed galleries deep in the endosperm of the berries, i.e. out of reach of the parasitoid. The potential of P. coffea for biological control of coffee berry borer in Colombia is discussed.     

Metaparasitylenchus hypothenemi n. sp. (Nematoda: Allantonematidae), a parasite of the coffee berry borer, Hypothenemus hampei (Curculionidae: Scolytinae)

Metaparasitylenchus hypothenemi n. sp. (Nematoda: Allantonematidae) is described from the coffee berry borer, Hypothenemus hampei (Ferrari) (Curculionidae: Scolytinae), in Chiapas, Mexico. This species differs from other members of the genus by its small size, annulated cuticle, lateral fields with 3 ridges, free-living stages with an excretory pore located between the pharyngeal gland orifices, a distinct stylet with basal swellings in free-living females, a postvulval uterine extension, a thin stylet lacking basal swellings in males, 2 separate spicules, a gubernaculum, and a peloderan bursa. Parasitic females are white, with a straight or slightly curved body and are ovoviviparous. Third-stage juveniles emerge from parasitized beetles and molt twice before reaching the adult stage. Because the coffee berry borer is the most important pest of coffee throughout the world and this parasite partially or completely sterilizes female beetles, it is worthy of further investigation as a potential biological control agent.     

Interactions among bethylid parasitoid species attacking the coffee berry borer,Hypothenemus hampei (Coleoptera: Scolytidae)

The question of whether biological control is most likely achieved by deploying single or multiple species of biological control agents is much debated. While utilizing several natural enemies may enhance control, there is also the potential for disruptive inter-specific interactions. Such interactions may be studied in the laboratory by focusing on the details of the interactions themselves and attempting to infer population level consequences from their sum, or by focusing more directly on the overall effects on natural enemy populations: we term these approaches ‘reductionist’ and ‘holistic.’ Here we conduct a holistic laboratory study on interactions between three species of parasitoid wasps that are parasitoids of the coffee berry borer, Hypothenemus hampei (Ferrari) (Coleoptera: Scolytidae): Cephalonomia stephanoderis Betrem, C. hyalinipennis Ashmead and Prorops nasuta Waterston (all Hymenoptera: Bethylidae). We find evidence for both intra- and inter-specific resource competition. Interactions between C. stephanoderis and P. nasuta, both indigenous to Africa, appear to be approximately symmetrical, while C. hyalinipennis, naturally found in the coffee plantations of Chiapas, Mexico, may exert a disruptive influence. C. hyalinipennis also has a low population growth rate. We now consider it to be a detrimental invader of the Mexican coffee agro-ecosystem that should not be encouraged by augmentative release or introduced into other regions. Overall, the most successful species, in terms of both emergence and female production, was P. nasuta. We compare these results with those from prior reductionist and holistic studies, and with observations on patterns of establishment of these bethylid species in the field. Given that it is increasingly clear that disruptive inter-specific interactions are generally common when multiple species are deployed in biological control, screening of potential agents should consider such interactions alongside the more ‘traditional’ focus on host specificity.     

Sequences and transcriptional analysis of Coffea arabica var. Caturra and Coffea liberica plant responses to coffee berry borer Hypothenemus hampei (Coleoptera: Curculionidae: Scolytinae) attack

The coffee berry borer (CBB) is the most prevalent pest of coffee plantations. Within the Coffea genus, C. arabica is susceptible to CBB and C. liberica shows a lower susceptibility. Two EST libraries were constructed from the total RNA of C. arabica and C. liberica fruits artificially infested with CBBs for 24 h. Using 6000 clones sequenced per library, a unigene database was generated, obtaining 3634 singletons and 1454 contigs. For each contig, the proportion of sequences present in both species was determined and a differential gene expression between the species was detected. C. arabica displayed a higher relative expression of proteins involved in general stress responses, whereas C. liberica showed the induction of a higher number of insect defense proteins. In order to validate the results, quantifications through real-time PCR were done. A hevein-like protein, an isoprene synthase, a salicylic acid carboxyl methyltransferase and a patatin-like protein gene were highly upregulated in C. liberica at 24 and/or 48 h after insect infestation compared to C. arabica. The identification of metabolic pathways induced by this pest insect provides tools to take advantage of the genetic resources available for the control of CBB.     

Sterility of the coffee berry borer,Hypothenemus hampei (Coleoptera: Curculionidae), caused by the nematode Metaparasitylenchus hypothenemi (Tylenchidae: Allantonematidae)

Metaparasitylenchus hypothenemi is an endoparasitic nematode that causes partial or total sterility of coffee berry borer (Hypothenemus hampei) females, although the causes are unknown. Fecundity and the average size of the common and lateral oviduct, vitellarium, and germarium in the four ovarioles (I, II, III and IV) were compared between parasitised and non-parasitised insects to determine the causes of sterility. The nematode significantly lowers the number of oocytes and 86% of parasitised insects (24 out of 28 insects) were sterile, while fecundity in the remaining 13% was non-significantly different to that in non-parasitised insects. No significant differences were recorded in the size of the common oviduct, lateral oviduct, vitellarium, and germarium between parasitised and non-parasitised insects and the nematode does not cause any apparent damage on the surface of the ovary.     

Evaluation of Beauveria bassiana (Ascomycota: Hypocreales) as a control of the coffee berry borer Hypothenemus hampei (Coleoptera: Curculionidae: Scolytinae) emerging from fallen,infested coffee berries on the ground

The effects of Beauveria bassiana strains on coffee berry borers (CBB), which emerge from infested berries left on soil, and its impact on the infestation of coffee berries on tree branches were evaluated at two Experimental Stations (Naranjal-Caldas and Paraguaicito-Quindio) in the Colombian coffee zone. Using a completely randomized design with 10 repetitions, 50 coffee berries artificially infested with CBB were placed on the base of a coffee tree. Four treatments including B. bassiana strain Bb9205, a mixture of Cenicafé strains (Bb9001, Bb9024 and Bb9119), a commercial formulation of B. bassiana and a control (water) were sprayed with 1×10⁹ conidia per tree. After 30 days, all fungal strains lowered the infestation levels of the coffee berries on the trees at both locations. The mixture of Cenicafé strains decreased the tree infestation between 50 and 30% at both locations. In the berries dissected from each treated tree, insect mortality was about 40% at both locations compared to 15% in the control. B. bassiana strains also decreased the insect population inside the newly infested berries on the trees by 55–75%. The mixture of Cenicafé strains was the most effective for decreasing insect populations. B. bassiana significantly decreased CBB populations that emerged from fallen, infested, coffee berries and reduced future insect generations.     

Evaluation of potential entomopathogenic fungus,Beauveria bassiana,for controlling the coffee berry borer Hypothenemus hampei (Ferrari) (Coleoptera: Curculionidae) in Taiwan

Hypothenemus hampei (Ferrari) (Coleoptera: Curculionidae: Scolytinae), a coffee berry borer (CBB), is a serious pest of coffee fruits and causes economic losses in the coffee industry. With the concerns of chemical control, an alternative eco-friendly management strategy such as microbial control has emerged as the times require. Herein, a total of thirty-three fungi were isolated from CBB cadavers. Two entomopathogenic fungal isolates, NCHU-271 and NCHU-272, which showed fast insect-killing activity, were subjected to molecular identification and named “Beauveria bassiana-NCHU-271” (Bb-NCHU-271) and “Beauveria bassiana -NCHU-272” (Bb-NCHU-272). Moreover, a virulence test of Bb-NCHU-271 and Bb-NCHU-272 against CBBs was also performed. Both Bb-NCHU-271 and Bb-NCHU-272 caused 100% mortality at 8 days post inoculation (d.p.i.) and a LT₅₀ of Bb-NCHU-271 by spraying 10⁸ conidia/ml was less than Bb-NCHU-272. Therefore, histological evidence of Bb-NCHU-271 infected CBBs was provided to proven the infection process of B. bassiana in CBBs. Furthermore, an infestation test was performed to evaluate the differences in CBB control efficacy between the treatments of “Borers exposed to EPF first” or “Berries exposed to EPF first”. The results revealed that the “Borers exposed to EPF first” of Bb-NCHU-272 caused significantly lower survival rates and higher mycosis rates than those of Bb-NCHU-271. Only slight control effects of Bb-NCHU-271 and Bb-NCHU-272 were also observed in the “Berries exposed to EPF” treatment. In conclusion, Bb-NCHU-271 and −272 showed controlling ability to the CBBs either before or after CBB infestation into coffee berries, while application of EPFs before the CBBs bored into coffee fruits could enhance the control effect.     

A review of the biology and control of the coffee berry borer, Hypothenemus hampei (Coleoptera: Scolytidae)

The coffee berry borer, Hypothenemus hampei Ferrari, is a serious problem for the majority of the world's coffee growers and has proved to be one of the most intractable of present day pests. Despite a great deal of research, control still depends largely on the application of the organochlorine insecticide endosulfan, which is damaging to the environment, or a series of cultural and biological control methods which give variable and unpredictable results. This review summarizes the most important aspects of the biology and ecology of H. hampei and its control and identifies weak points in the knowledge about this pest. Emphasis is placed upon an analysis of the non-chemical control methods available and suggestions are offered for novel ecological and environmental factors worthy of further research, in the search for viable and sustainable control methods.     

Natural occurrence of Beauveria bassiana in Hypothenemus hampei (Coleoptera: Curculionidae) populations in unsprayed coffee fields

Three unsprayed coffee farms (farm 1, 2 and 3) were studied for the natural occurrence of the insect pathogenic fungus Beauveria bassiana in Hypothenemus hampei populations throughout the rainy season of 2004 (July-November) and 2005 (July-December). B. bassiana infections were found during most sampling dates in both years, on all three farms. The B. bassiana infection levels were higher in 2005 than in 2004 with mean prevalence of 12.1% and 2.7%, respectively. No consistent significant differences in infection level between farms were found in any of the years. B. bassiana infection levels fluctuated widely throughout the season, and peaked at 13.5% on farm 3 in 2004 and at 44.0% on farm 1 in 2005. The H. hampei population was significantly higher in 2004 than in 2005, with 6.9% of the berries infested in 2004 and only 0.7% in 2005. In both years, the H. hampei infestation level was significantly higher on farm 2. No consistent significant differences in H. hampei infestation levels were found between sampling dates on any of the farms. H. hampei infestation levels fluctuated throughout both seasons, and peaked at 15.3% on farm 2 in 2004 and 2.2% on farm 2 in 2005. No consistent density dependent correlation between H. hampei infestation level and B. bassiana infection level was found. Correlations between climatic conditions and B. bassiana or H. hampei were not found.     

Economic injury level for the coffee berry borer (Coleoptera: Curculionidae: Scolytinae) using attractive traps in Brazilian coffee fields

The currently existing sample procedures available for decision-making regarding the control of the coffee berry borer Hypothenemus hampei (Ferrari) (Coleoptera: Curculionidae: Scolytinae) are time-consuming, expensive, and difficult to perform, compromising their adoption. In addition, the damage functions incorporated in such decision levels only consider the quantitative losses, while dismissing the qualitative losses. Traps containing ethanol, methanol, and benzaldehyde may allow cheap and easy decision-making. Our objective was to determine the economic injury level (EIL) for the adults of the coffee berry borer by using attractant-baited traps. We considered both qualitative and quantitative losses caused by the coffee borer in estimating the EILs. These EILs were determined for conventional and organic coffee under high and average plant yield. When the quantitative losses caused by H. hampei were considered alone, the EILs ranged from 7.9 to 23.7% of bored berries for high and average-yield conventional crops, respectively. For high and average-yield organic coffee the ELs varied from 24.4 to 47.6% of bored berries, respectively. When qualitative and quantitative losses caused by the pest were considered together, the EIL was 4.3% of bored berries for both conventional and organic coffee. The EILs for H. hampei associated to the coffee plants in the flowering, pinhead fruit, and ripening fruit stages were 426, 85, and 28 adults per attractive trap, respectively.     

Bacillus thuringiensis serovar israelensis is highly toxic to the coffee berry borer, Hypothenemus hampei Ferr. (Coleoptera: Scolytidae)

A native collection of Bacillus thuringiensis strains was screened, once a reliable bioassay technique to assess the toxicity against the coffee berry borer (CBB) first-instar larvae was developed. A first round of bioassays with 170 strains indicated that the great majority of them showed no or very little insecticidal activity and that very few showed significant levels of toxicity. Interestingly, only those strains that had previously been associated with mosquitocidal activity were also toxic to CBB. Qualitative bioassays (using one high dose) were carried out only with those native mosquitocidal strains, corroborating their significant toxicity towards the CBB first-instar larvae. Most of these strains belong to serovar israelensis. In a second approach, strains from the Institut Pasteur type collection, whose mosquitocidal activity had been previously demonstrated, were also subjected to bioassays. Only those strains that showed a comparable protein content in their parasporal crystals to the israelensis type strain also showed high levels of toxicity towards CBB. Finally, an accurate LC(50) was estimated, using purified parasporal crystals from B. thuringiensis serovar israelensis type strain, at 219.5 ng cm(-2) of diet. All the statistical requirements for a reliable estimator were fulfilled. This is the first report of B. thuringiensis serovar israelensis being active against a coleopteran species.     

Areography of the genus Dendroctonus (Coleoptera: Curculionidae: Scolytinae) in Mexico

Objective To analyse whether the geographical ranges of Dendroctonus species are (1) associated with factors such as host species or elevation, and (2) in agreement with Halffter's Nearctic distribution pattern. (3) To identify and discuss the factors that are likely to act as barriers to the genus’ geographical distribution. (4) To explore whether there is an association between the size of the geographical ranges of Dendroctonus species and the number of Pinus host species used by each of them, and (5) to assess if these host species are most common at the elevations preferred by the individual Dendroctonus species. Site Mexico. Methods Records of 12 species of Dendroctonus were gathered from entomological collections in Mexico. Distribution ranges were defined by using the propinquity method ( Rapoport, 1975a ). Analysed parameters were: (1) geographical distribution of single species, (2) overlapping of species ranges, (3) disjunction patterns and barriers by means of isoprobabilistic lines, based on the morphotectonic subdivision of Mexico ( Ferrusquía‐Villafranca, 1998 ), (4) spatial variation in species richness with respect to latitude and altitude, (5) size of geographical ranges, and (6) host species for each Dendroctonus species. A correlation was determined between area size and number of pine host species. Results The species ranges varied in shape and size. Geographical ranges tend to be discontinuous in shape. Composite patterns showed that disjunctions among ranges do not closely follow Mexico's morphotectonic subdivision. There are repeated discontinuities among individual distributions, which define five areas: (1) Baja California Peninsula, (2) Sierra Madre Occidental (SMOC), (3) northern Sierra Madre Oriental (SMOR), (4) Sierra Madre de Chiapas, and (5) SMOR + Faja Volcanica Transmexicana (FVT) + Sierra Madre del Sur. The isoprobabilistic lines confirm that the inner part of SMOC provides an optimal environment for the genus, and the FVT province constitutes the broader corridor for it in the country. Richness does not directly decrease or increase with latitude. Richness behaviour of the insect is not associated with that of its host. Elevation distributions showed that most Dendroctonus species move within broad margins of tolerance and species richness is concentrated in the montane interval. Dendroctonus attack 24 of the 47 Pinus species distributed in Mexico. Preferred pine species belong predominantly to Leiophyllae, Ponderosae and Oocarpae subsections. The Spearman rank correlation between area size and number of pine host species was not significant. Dendroctonus clearly belongs to a Nearctic distribution pattern (sensu Halffter, 1987 ). Main conclusions Dendroctonus is present in all montane systems of Mexico and its species coexist within a high geographical sympatry. Overlapping of species distribution appears to be the result of two elements – generalized polyphagy inside Pinus and a wide elevation tolerance within mountainous environments. This behaviour, linked to a high vagility, has allowed the genus Dendroctonus to expand its distribution across Mexico and to employ mountainous systems as corridors separated by barriers that exert a low selective filter effect.     

Some like it hot: the influence and implications of climate change on coffee berry borer (Hypothenemus hampei) and coffee production in East Africa

The negative effects of climate change are already evident for many of the 25 million coffee farmers across the tropics and the 90 billion dollar (US) coffee industry. The coffee berry borer (Hypothenemus hampei), the most important pest of coffee worldwide, has already benefited from the temperature rise in East Africa: increased damage to coffee crops and expansion in its distribution range have been reported. In order to anticipate threats and prioritize management actions for H. hampei we present here, maps on future distributions of H. hampei in coffee producing areas of East Africa. Using the CLIMEX model we relate present-day insect distributions to current climate and then project the fitted climatic envelopes under future scenarios A2A and B2B (for HADCM3 model). In both scenarios, the situation with H. hampei is forecasted to worsen in the current Coffea arabica producing areas of Ethiopia, the Ugandan part of the Lake Victoria and Mt. Elgon regions, Mt. Kenya and the Kenyan side of Mt. Elgon, and most of Rwanda and Burundi. The calculated hypothetical number of generations per year of H. hampei is predicted to increase in all C. arabica-producing areas from five to ten. These outcomes will have serious implications for C. arabica production and livelihoods in East Africa. We suggest that the best way to adapt to a rise of temperatures in coffee plantations could be via the introduction of shade trees in sun grown plantations. The aims of this study are to fill knowledge gaps existing in the coffee industry, and to draft an outline for the development of an adaptation strategy package for climate change on coffee production. An abstract in Spanish is provided as Abstract S1.     

The Banded Elm Bark Beetle, Scolytus schevyrewi Semenov (Coleoptera, Curculionidae, Scolytinae) in North America: a taxonomic review and modifications to the Wood (1982) key to the species of Scolytus Geoffroy in North and Central America

In 2003, an Asian bark beetle, Scolytus schevyrewi Semenov (Coleoptera: Curculionidae: Scolytinae), the banded elm bark beetle, was detected for the first time in North America. This paper modifies the Wood (1982) key to the species of Scolytus Geoffroy to enable identification of Scolytus schevyrewi in North and Central America. Variation of diagnostic characters in Scolytus schevyrewi is discussed.     

Investigating the abundance and flight period of bark beetles (Coleoptera: Curculionidae: Scolytinae) over elevational gradients in Sitka spruce forests

1. A warming climate, as predicted under current climate change projections, is likely to influence the population dynamics of many forest insect species. Numerous bark beetle species in both Europe and North America have already responded to a warming climate by significantly expanding their geographical ranges.
2. The aim of the current study was to investigate how populations of bark beetles within stands of Sitka spruce, a widely planted non-native commercial plantation tree species in the U.K., were likely to respond to a warming climate. Experimental plots were established in stands of Sitka spruce over elevational gradients in two commercial forest plantations, and the abundance and emergence times of key bark beetle species were assessed over a 3-year period using flight interception traps. The air temperature difference between the lowest and highest experimental plot in each forest was consistently >1°C throughout the 3-year period.
3. In general, the abundance of the most dominant bark beetle species (e.g. Trypodendron, Dryocoetes, Hylastes spp.) was higher, and emergence times tended to be earlier in the year at the lower elevation plots, where temperatures were higher, although not all bark beetle species responded in the same manner.
4. The results of the study indicated that, under the projected future climate warming scenarios, monoculture Sitka spruce stands at low elevations may potentially be more vulnerable to significant outbreak events from existing or invasive bark beetle species. Hence, consideration of establishing more resilient forests of Sitka spruce by diversifying the species composition and structure of Sitka spruce stands is discussed.