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Increasing demand for wood is putting pressure on forest resources that are equally under threat from insect pests and diseases. Reported average annual forest loss stands at 0.2% globally, 0.8% in Africa, and 1.6% in Kenya. To meet the increasing demand for forest products in Kenya, the government and private sector have established plantations of non-native tree species dominated by Eucalyptus species, Cupressus lusitanica, and Pinus patula. To ensure successful forest plantation establishment and management schemes, there is a need for sufficient knowledge and understanding of tree growth conditions and threats including pests and diseases. This study aimed at determining the incidence of plantation and tree nurseries in Kimondi Forest, Kenya. Tree plantations were mapped into 2.5 Ha rectangular portion transects parallel to the forest roads. In randomly selected portions, observations were carried out for disease and pest signs and symptoms on various tree parts (leaves, stem, roots, fruits, and twigs). In the tree nurseries, 3 m × 1 m rectangular quadrants were placed on seedling beds and similar observations were made. Collected data indicated a high incidence of nursery seedling pests (5.3 % leaves and 5.1% stems) on Eucalyptus species and least on P. patula (2.4% leaves and 3% stems). Higher incidence of plantation pests (35.0% leaves of Eucalyptus sps.) and least on P. patula stems (1.2%) were recorded. On the other hand, twelve (12.0%) of C. lusitanica and (1.8%) Eucalyptus species plantation twigs were infested by pests. A high incidence of nursery seedling disease (9.8%) was observed on C. lusitanica leaves and least on P. patula stems (3.6%). Higher incidence of plantation diseases (32 %) on leaves of Eucalyptus sps. and least on C. lusitanica stem (1.4%) was recorded. In both tree nurseries and plantations, roots and fruits remained free from pests and disease. Major tree pests and diseases identified in Kimondi forests include (Human, wildlife, livestock, Cinara cupressi, Gonipterus scutellatus, Pinus pini, and Leptocybe invasa) and (damping-off, Fusarium wilt, Botryosphaeria canker, cypress canker, and Mycosphaerella spp.) respectively. These results suggest a need for regular monitoring and intervention measures to control pest and disease infestation in the Kimondi forest.

is a beetle causing severe defoliation to South Africa’s eucalyptus plantations. This defoliation induced by the beetle inhibits the eucalypts ability to photosynthesize, by affecting its chlorophy...

Gonipterus scutellatus (Coleoptera: Curculionidae), once thought to be a single species, is now known to reside in a complex of at least eight cryptic species. Two of these species (G. platensis and G. pulverulentus) and an undescribed species (Gonipterus sp. n. 2) are invasive pests on five continents. A single population of Anaphes nitens, an egg parasitoid, has been used to control all three species of Gonipterus throughout the invaded range. Limited knowledge regarding the different cryptic species and their diversity significantly impedes efforts to manage the pest complex outside the native range. In this review, we consider the invasion and taxonomic history of the G. scutellatus cryptic species complex and the implications that the cryptic species diversity could have on management strategies. The ecological and biological aspects of these pests that require further research are identified. Strategies that could be used to develop an ecological approach towards managing the G. scutellatus species complex are also suggested.

The study was initiated by the relative failure of the parasitoid Anaphes nitens in controlling the eucalypt weevil Gonipterus platensis on the Iberian Peninsula. Our aim was to gain insight into the community of Gonipterus egg parasitoids occurring in Tasmania. During surveys in 2016 and 2017, adult weevils and egg pods were collected from Eucalyptus trees in Tasmania. The weevils were identified using male genital structure and DNA extracted from hatched larvae. Parasitoids that emerged from the egg pods were identified, and trophic associations of egg parasitoids, weevils and host plants were analyzed. Five species of the Gonipterus scutellatus complex, to which G. platensis belongs, were found, including Gonipterus sp. 2, which is reported for the first time from Tasmania. Molecular analysis corroborated previous phylogenetic studies of this group of species. A sixth species, G. notographus, was also collected. Most species were found to overlap in distribution in Tasmania and, despite being oligophagous, to display selectivity among Eucalyptus species used as hosts: G. platensis and G. pulverulentus were mainly found on E. ovata, Gonipterus sp. 1 on E. nitens and E. globulus and G. notographus on ‘peppermint’ species (E. amygdalina and E. pulchella). Five egg parasitoid species were found associated with these Gonipterus species: Anaphes inexpectatus, A. nitens, A. tasmaniae, Cirrospilus sp. and Euderus sp., with no apparent host specialization. Anaphes nitens, Cirrospilus sp. and Euderus sp. were more frequently found on E. ovata, possibly associated with G. platensis and G. pulverulentus, which were dominant on this host species. Conversely, A. inexpectatus was dominantly found on peppermints (43%), suggesting a main association with G. notographus. Anaphes nitens was found at 23 locations out of 117 and in 2017 was the most abundant parasitoid obtained, with an average 20% parasitism rate, indicating that this species is undergoing a geographical and population expansion since its first report from Tasmania in 2012. These findings contribute to the understanding of the parasitoid-Gonipterus-Eucalyptus trophic relationship and stand to improve future classical biological control programs against G. platensis and other invasive Gonipterus species.

Gonipterus scutellatus outbreaks may severely defoliate Eucalyptus plantations growing in South Africa. Therefore, detecting and mapping the severity and extent of G. scutellatus defoliation is essential for the deployment of suppressive measures. In this study, we tested the utility of spatially optimized vegetation indices and an artificial neural network in detecting and mapping G. scutellatus-induced vegetation defoliation, using both visual estimates of percentage defoliation and optical leaf area index (LAI) measures. We tested both field methods to determine which of the two were more superior in detecting vegetation defoliation using optimized vegetation indices. These indices were computed from a WorldView-2 pan-sharpened image, which is characterized with a 0.5-m spatial resolution and eight spectral bands. The indices were resampled to spatial resolutions that best represented levels of G. scutellatus-induced defoliation. The results showed that levels of defoliation, using visual perce...

Gonipterus scutellatus Gyllenhal is a leaf feeding weevil that is a major defoliator of the genus Eucalyptus . Understanding the relationship between levels of weevil induced vegetation defoliation and the optimal spatial resolution of satellite images is essential for effective management of plantation resources. The objective of this study was to identify appropriate spatial resolutions for predicting levels of weevil induced defoliation. We resampled the Normalized Difference Vegetation Index (NDVI), Simple Ratio (SR) and Enhanced Vegetation Index (EVI) images computed from a WorldView-2 pan-sharpened image, which is characterised with a 0.5 m spatial resolution and 8 spectral bands. Within each plantation compartment 30 × 30 m plots were established, representing different levels of defoliation. From the centre of each plot, the spatial resolution of the original image was progressively resampled from 1.5 to 8.5 m, with 1 m increments. The minimal variance for each level of defoliation was then established and used as an indicator for quantitatively selecting the optimal spatial resolution. Results indicate that an appropriate spatial resolution was established at 1.25, 1.25, 1.75 and 2.25 m for low, medium, high and severe levels of defoliation, respectively. In addition, an Artificial Neural Network was run to determine the relationship between the appropriate spatial resolution and levels of Gonipterus scutellatus induced defoliation. The model yielded an R 2 of 0.80, with an RMSE of 1.28 (2.45% of the mean measured defoliation) based on an independent test dataset. We then compared this model to a model developed using the original 0.5 m image spatial resolution. Our results suggest that optimising the spatial resolution of remotely sensed imagery essentially improves the prediction of vegetation defoliation. In essence, this study provides the foundation for multi-scale defoliation mapping using high spatial resolution imagery.

The Panel on Plant health performed a pest categorisation of the Australian Eucalyptus snout-beetle Gonipterus scutellatus (Coleoptera: Curculionidae), for the EU. G. scutellatus should be referred as the G. scutellatus species complex because it includes several cryptic species. A complete nomenclature of the species present in the EU is still pending. It is a quarantine pest listed in Annex IIB of Council Directive 2000/29/EC. Protected zones are in place in Greece and Portugal (Azores). In the EU, it has been found in Italy, France, Spain and Portugal. It only consumes Eucalyptus species leaves. The main pathways of spread are the trade of Eucalyptus timber, hitchhiking in various commodities, trade of apple fruit as well as of plants for planting or plant parts. Spread by fl ight is also possible. The climate of the EU protected zones is similar to that of the Member States (MS) where the G. scutellatus complex is established, and the pest ’ s main host plants are present. The damaged trees suffer die-back and the development of epicormics shoots. Severe attacks may provoke massive amounts of tree death. Biological control by using the egg parasitoid wasp Anaphes nitens is the most effective control measure. Some species within the G. scutellatus complex are not yet present in the EU (including G. scutellatus sensu stricto) and might therefore be considered as potential union quarantine pests for the EU territory. At least two species within the G. scutellatus complex (most likely G. platensis and Gonipterus species no. 2) meet the criteria assessed by EFSA for consideration as potential protected zone quarantine pests for the territory of the protected zones: Greece and Portugal (Azores). The criteria for considering the G. scutellatus complex as a potential regulated non- quarantine pest for the EU are not met since plants for planting are not the main pathway.

Defoliation induced by the weevil Gonipterus scutellatus is causing significant damage to South Africa’s eucalyptus plantations. Therefore, the ability of remote sensing to detect and map G. scutellatus defoliation is essential for monitoring the spread of the weevil so that precautionary measures are set in place. In our study, an integrated approach using image texture in various processing combinations and an artificial neural network (ANN) were developed to detect and map G. scutellatus induced vegetation defoliation. A 0.5-m WorldView-2 pan-sharpened image was used to compute texture parameters from the gray-level occurrence matrix and gray-level co-occurrence matrix, using optimal moving windows for specific levels of G. scutellatus induced vegetation defoliation. In order to improve the accuracy of detecting and mapping G. scutellatus induced vegetation defoliation, a method involving a three-band texture processing combination was proposed and tested. Using a sequential forward selection algorithm allowed for the selection of optimal texture combinations, which were subsequently input into a backpropagation ANN. The results showed an improvement in detecting vegetation defoliation using single texture bands [R2 = 0.82, root mean square error (RMSE) = 0.95 (1.82% of the mean measured defoliation)] when compared to single spectral reflectance bands [R2 = 0.60, RMSE = 1.79 (3.43% of the mean measured defoliation)], two-band spectral reflectance combination model [R2 = 0.74, RMSE = 1.48 (2.83% of the mean measured defoliation)], and the three-band spectral reflectance combination model [R2 = 0.80, RMSE = 1.35 (2.59% of the mean measured defoliation)]. Further improvements were obtained using the two-band texture combination model [R2 = 0.85, RMSE = 1.05 (2.01% of the mean measured defoliation)] and the most promising result was obtained using the proposed three-band texture combination model [R2 = 0.90, RMSE = 0.85 (1.63% of the mean measured defoliation)]. Overall, our study highlights the potential of image texture combinations in improving the detection and mapping of vegetation defoliation.

Australian-origin pests of eucalypts have been moving around the world almost as long as the trees themselves. Up until the 1990’s there was a steady linear increase in the numbers of these pests establishing overseas, with relatively slow subsequent movement. Under this scenario, traditional approaches to classical biological control - where individual countries or regions funded natural enemy searches in Australia, carried out required specificity testing and released the agents - were effective. However, since the 1990’s, the establishment rate of new pests has increased almost exponentially (correlated with enormously increased trade and people movement) with rapid subsequent invasion of these pests into new countries and across continents exacerbating the problem. This has necessitated new approaches to developing biological control programs, with individual countries less able to cope with multiple pests arriving almost simultaneously. A globally collaborative approach to biological control is therefore required, where funds and expertise can be effectively and cost-efficiently pooled and shared to develop biological control for these eucalypt pests. Methods: A collaborative framework has been developed by industry and researchers worldwide to solve this problem through the formation of the BiCEP (Biological Control of Insect Pests) Alliance. BiCEP is targeting research in Australia and overseas on major pests (e.g. Gonipterus scutellatus complex, Glycaspis brimblecombei) prioritised by its industry partners. Results/Conclusion: Early conclusions from this approach, practical outcomes from current research, and future directions and improvements will be discussed.

Programa de Posgrado

The Mediterranean climate zone in North America is restricted to the states of California in the USA and parts of Baha California Norte in Mexico. As described in other chapters in this volume, the climate is characterized by cool wet winters and hot dry summer conditions. The greatest amount of precipitation falls in the late fall and winter months. The remainder of the year is dry. Eucalypts were introduced from Australia as seed in the mid nineteenth century and have been widely planted in California. Although there have been a few rare reports of occasional host use, no native insect species have undergone a host shift onto the trees. Until the mid 1980s there were only two exotic insects that feed on eucalypts introduced from Australia to California. In a 20 year period beginning in 1984, 16 exotic insects from four feeding guilds established in the state. Three of these insects are under complete biological control [the blue gum psyllid (Ctenerytinae eucalypti (Maskell)), the eucalyptys longhorned borer (Phoracantha semipunctata F), and the eucalyptus snout weevil (Gonipterus scutellatus Gyll.)] are under complete biological control. Several more [the red gum lerp psyllid (Glycaspsis brimblecombei Moore), the lemon gum psyllid (Cryptoneossa triangular Taylor), the spotted gum psyllid (Eucalytolyma maideni Froggatt), and, possibly, a second longhorned borer (Phoracantha recurva Newman)] are under partial biological control. The introductions have continued since 2004, but at a much slower pace than the previous 20 years. Although there have been differences in the patterns of introductions of insects that feed on eucalypts in different Mediterranean climates zones, the community of insects is becoming homogenized as movement of people and goods continues to spread the insects into new areas. The management approaches developed in one part of the Mediterranean world will find broader applications in other parts of that world as the movement of invasive arthropods continues.