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Red palm weevil (RPW) Rhynchophorus ferrugineus (Olivier 1790) is a highly invasive species originating from Southeast Asia and Melanesia. Over the past 30 years, this alien pest has spread extensively in the Middle East and the Mediterranean basin. Its endophagous larvae feed on various palm species, causing significant damage that leads to the death of palm trees. Controlling RPW infestations is challenging due to their gregarious nature and the lack of detectable early symptoms. Systemic insecticides are effective means of control, but their use in urban areas is prohibited and resistance can develop. Considering alternative options with minimal environmental impact, the Sterile Insect Technique (SIT) has been explored. Previous research has shown that male RPWs irradiated at 80 Gy or higher achieve full sterility. This study aimed to investigate in laboratory conditions whether RPW sterile males (irradiated at 60 and 80 Gy) could compete sexually with non-irradiate males. Laboratory bio-assays under both no-choice and choice conditions assessed sexual performance in terms of number of matings, mating duration and time elapsed until the first mating. The results confirmed that irradiation does not negatively affect the mating performance of sterile males, demonstrating their ability to compete successfully with non-irradiated males in both experimental setups.

BACKGROUND: Essential oils extracted from aromatic and medicinal plants have many biological properties and are therefore an alternative to the use of synthetic products. The chemical composition of essential oils from two medicinal plants (Eucalyptus globulus and E. lehmannii) was determined and, their insecticidal effects on the third and fourth larval stages of Orgyia trigotephras were assessed. RESULTS: Larvae were collected from Jebel Abderrahmane (North-East of Tunisia), conserved in groups of 50/box (21 × 10 × 10 cm) at a temperature of 25°C. Larvae were tested for larvicidal activities of essential oils. Each oil was diluted in ethanol (96%) to prepare 3 test solutions (S1 = 0.05%, S2 = 0.10% and S3 = 0.50%). Essential oils were used for contact, ingestion and Olfactory actions and compared to reference products (Bacillus thuringiensis and Decis). Olfactory action of essential oils shows that larvae mortality is higher than contact action, lower than ingestion action. MTM and FTM of S3 of E. lehmannii were respectively 1 h 32 min and 1 h 39 min are higher than those of E. globulus (MTM = 51 min and FTM = 1 h 22 min 34 sec). Contact action of E. lehmannii oil shows low insecticidal activity compared to E. globulus. MTM are respectively (1 min 52 sec and 1 min 7 sec), FTM are (2 min 38 sec, 1 min 39 sec), are the shortest recorded for S3, on the third stage of larvae. The fourth stage of larvae, MTM are (2 min 20 sec and 2 min 9 sec), FTM are (3 min 25 sec, 3 min 19 sec). Ingestion action of essential oils is longer than the contact action, since the time of death exceeds 60 minutes for all species. CONCLUSION: Results shows that essential oils have a toxic action on nerves leading to a disruption of vital system of insects. High toxic properties make these plant-derived compounds suitable for incorporation in integrated pest management programs.

Abstract Background Trichoderma species are able to cause significant changes in the metabolism of host plants, by that means it trigger the plant growth and increasing plant defense to diverse fungal diseases. Trichoderma harzianum has been identified as potential biocontrol agent of many phytopathogenic fungi. Therefore, the aim of this study was to assess in vitro antagonistic activity against three Diplodia isolates utilizing direct and remote confrontations methods. Results The results revealed that T. harzianum inhibited mycelial growth of the three phytopathogenic fungi compared to the untreated control. The percentage of growth inhibition of T. harzianum against Diplodia isolates ranged between 58 and 79% for direct confrontation and between 31 and 46% remote confrontation. Considerable antagonistic abilities of T. harzianum were exhibited against all tested Diplodia isolates. The results of both confrontations showed that the radial growth of the fungal pathogens was statistically significant (P

Abstract Background The tachinid parasitoid, Exorista segregata (Rondani, 1859) (Diptera: Tachinidae) is a polyphagous fly recorded on larvae of lepidopterans. Larvae of the Erebidae, Orgyia trigotephras Boisduval were collected from Northern Tunisia and reared in the laboratory at INRGREF. Larvae were kept individually until emergence of parasitoid’s adults. Results Morphological data including dissected genitalia was used to identify E. segregate as a parasitoid of O. trigotephras larvae. Conclusion The larval parasitoid, E. segregata is recorded from a new host O. trigotephras for the first time in Tunisia. This species could be considered in the programs of biological control of different lepidopterans’ pests in Tunisia and neighboring countries.

Abstract Background The polyphagous tachinid Compsilura concinnata is an endoparasitoid fly recorded as attacking larvae of Lepidoptera and Hymenoptera. Larvae of Orgyia trigotephras [Lepidoptera: Erebidae] were collected from northern Tunisia and reared in the laboratory. Results Adult flies that emerged from these larvae were identified on the basis of morphological description and DNA analysis (PCR) as Compsilura concinnata. Conclusion Compsilura concinnata is recorded here for the first time from Orgyia trigotephras in Tunisia. This species could be of great interest as a potential biological control agent of pests in Tunisia and neighboring countries.

Ezzine, O., Chograni, H., Dhahri, S., and Ben Jamâa, M.L. 2020. Defense of host plants against Orgyia trigotephras in north-east Tunisia. Tunisian Journal of Plant Protection 15 (2): 81-89.

Abstract Numerous studies have shown that the genetic diversity of species inhabiting temperate regions has been shaped by changes in their distributions during the Quaternary climatic oscillations. For some species, the genetic distinctness of isolated populations is maintained during secondary contact, while for others, admixture is frequently observed. For the winter moth (Operophtera brumata), an important defoliator of oak forests across Europe and northern Africa, we previously determined that contemporary populations correspond to genetic diversity obtained during the last glacial maximum (LGM) through the use of refugia in the Iberian and Aegean peninsulas, and to a lesser extent the Caucasus region. Missing from this sampling were populations from the Italian peninsula and from North Africa, both regions known to have played important roles as glacial refugia for other species. Therefore, we genotyped field‐collected winter moth individuals from southern Italy and northwestern Tunisia—the latter a region where severe oak forest defoliation by winter moth has recently been reported—using polymorphic microsatellite. We reconstructed the genetic relationships of these populations in comparison to moths previously sampled from the Iberian and Aegean peninsulas, the Caucasus region, and western Europe using genetic distance, Bayesian clustering, and approximate Bayesian computation (ABC) methods. Our results indicate that both the southern Italian and the Tunisian populations are genetically distinct from other sampled populations, and likely originated in their respective refugium during the LGM after diverging from a population that eventually settled in the Iberian refugium. These suggest that winter moth populations persisted in at least five Mediterranean LGM refugia. Finally, we comment that outbreaks by winter moth in northwestern Tunisia are not the result of a recent introduction of a nonnative species, but rather are most likely due to land use or environmental changes.

The Tunisian fauna of Tortricidae has been poorly investigated despite the great economic importance of this family. Sampling of Tortricidae insects was carried out in spring and summer 2010 in two cork oak (Quercus suber) forestsin northwestern Tunisia. Three species are reported for the first time: Archips xylosteana, Pammene splendidulana, Pammene giganteana. Their identification was achieved using DNA barcodes.

The Tunisian oak forests are susceptible and sensitive to invasion of various pests, among them, the green oak leaf roller, Tortrix viridana, which is considered one of the most destructive defoliators of oak trees in the western Palearctic region. Important defoliations caused by this pest have been observed in different cork oak forests of north-western Tunisia. The study was carried out in five native cork oak (Quercus suber) forests (Ain El Baya, Bellif 1, Bellif 2, Bellif 10, and El Jouza), one zeen oak (Q. canariensis) forest Mzara and the Ain Zena forest which is a mixed cork oak, zeen oak and afares oak (Q. afares) located in the north-west of Tunisia. The average number of larvae per branch varied significantly between sites (6.6 ± 0.77 larvae/branche in El jouza and 0.11 ± 0.05 larva/branche on Q. afares in Ain Zena forest). Budburst timing did not differ between Q. canariensis and Q. afares whereas that of Q. suber occurred about 3 weeks later than the other two species. As the host plant phenology differs from species to another, the larval survival and their development are likely different across the host plant species. Feeding performance of the green oak leaf roller was determined on three host plants including Q. suber, Q. canariensis and Q. afares under laboratory conditions. Larvae grew best on Q. suber. Total larval development time from the 1st to the 5th instar was shorter on Q. suber (24.92 ± 0.26 days) than on Q. canariensis (26.69 ± 0.29 days ) and Q. afares (29.03 ± 0.39 days). Larval mortality of the three host plants did not differ significantly while for the pupal weight, data showed a significant difference where 35.52 ± 9.44, 30.43 ± 8.25, and 22.95 ± 5.34 mg of pupae from the larvae reared on Q. suber, Q. canariensis and Q. afares were noted, respectively

Trichoderma harzianum is an endophyte fungus of considerable interest because of its effectiveness as a biocontrol agent against various plant pathogenic fungi. In this study, T. harzianum was isolated from cork oak trees in three forests in northwest Tunisia. Initially, the fungal characterization was carried out based on macroscopic and microscopic features. Sequencing of the internal transcribed spacers 1 and 2 of the DNAr was carried out to confirm fungus identification at the species level. The aims of this work were to study the occurrence of T. harzianum, to understand its relationship with the host plant, and to quantitatively investigate its distribution on the different organs of cork oak trees across three sites (Babouch, Ain snoussi, Ain zana). T. harzianum frequency varied significantly (P inferieur 0.001) among the surveyed forests. The fungus was more common at Babouch forest and was rarely encountered at Ain zana. Correlation analysis was used to determine the relationship between the dendrometric parameters, the phytosanitary status of the investigated trees and the abundance of T. harzianum. The results showed a significant and positive correlation between the fungus frequency and the tree height. A negative and significant correlation was noted between the trees’ chlorosis index and fungus abundance. These findings may afford a contribution to the knowledge of T. harzianum in Tunisian forests and its relationship with cork oak trees which could help to develop control strategies using Trichoderma strains.

In Tunisia, Lobesia botrana is a pest of grapevine. Larvae of L. botrana were observed for the first time in 2014 in Sejnane (Northwestern Tunisia) on Daphne gnidium and more recently, in 2017, in Delhiza (Northeastern Tunisia). Larvae need to enter into a bud at budburst to feed on young leaves. Pupae were observed from the end of May to early June on D. gnidium buds and adults emerged in June. After mating, female lays eggs by mid-June. In this paper, we present a first report of L. botrana on D. gnidium in Tunisia.

Cork oak (Quercus suber) is a unique species of the Western Mediterranean region and over the last decades it has been threatened by several pests and diseases. Amongst the main dangerous pests, the ambrosia beetle Platypus cylindrus (the oak pinhole borer) has a key role on the process of cork oak decline namely in Portugal, Morocco, and Algeria. However, in Tunisia, where cork oak forests cover around 90.000 ha of the territory, this insect continues to have a secondary pest status. As all ambrosia insects, P. cylindrus is able to establish symbiotic relationships with fungi and it is known as the vector of ophiostomatoid fungi, a group including primary tree pathogens. The aim of this study was to identify these beetle-associated fungi in Tunisian forests and to understand the contribution of this association in cork oak decline by comparing with the results from other countries. The present study was conducted in 2012 in ten cork oak forests in the western-north of Tunisia and focused on ophiostomatoid fungi associated with the cork oak pinhole borer. Twenty four isolates were grouped based on morphological identification, and five representative isolates were included in phylogenetic analyses based on sequence data of ITS and β-tubulin loci. The fungi were assigned to five species namely Raffaelea montetyi, R. canadensis, Ophiostoma sp., O. tsotsi and O. quercus, some of them were already reported in Portugal and Algeria to be associated with cork oak decline. All these species were identified and reported for the first time in Tunisia to be associated with P. cylindrus in cork oak trees and their role in the cork oak loss of vitality needs to be investigated.

In Tunisia, larvae of Anacampsis scintillella were observed for the first time in 2010, on Halimium halimifolium. Preliminary investigations on biological behavior of A. scintillella were carried out in Bizerte (Sejnane) in 2017. To estimate the level of host plant infestation, the number of A. scintillella shelters found was counted and the collected individuals were subjected to biological study. The mean number of shelters was 5.4 per plant. Larvae of A.scintillella stick leaves (4-34, mean of 13 leaves) together by means of silkthreads to form a distinctive pouch like shelter within which the larva feeds.Larvae were observed from April to early May. Chrysalis was observed from early May to midMay. Adult flight occurs from late May to early June.

Ornamental palm tree Phoenix canariensis has been introduced in Tunisia at late 1800's and becomes a symbol of the city landscape in different localities. P. canariensis was seriously attacked since 2011 by the red palm weevil (RPW), Rhynchophorus ferrugineus. Recently a new pest Potosia opaca was detected in North of Tunisia on living P. canariensis trees solely or associated with RPW. P.opaca develops one generation per a year; adult mating takes place in June-July and females lay in humus inside decayed trunks of living palms tree. Larva lives in most accumulations of organic matter inside trunks between fibers and sheaths into close proximity with live wood. The pupa stage lasts on average 50 days. P.opaca lives on living trees and seems not to be associated with tree mortality. However it is essential to consider a number of indirect damage as this insect is likely becoming a vector of many pathogens.

At the end of December 2009, an important defoliation of Acacia horrida was observed in the southern part of Tunisia, at Jebel Brourmet, Tataouine. Mature larvae, pupae and egg masses of Casama innotata were observed on defoliated A. horrida trees. In this paper, we presented a first report of this species in Tunisia.

In 2012, Deudorix livia was responsible for severe losses in production of pomegranate trees in the regions of Gafsa and Gabes situated in Southern of Tunisia. D. livia was observed on some pods of Acacia farnesiana planted as windbreak around these orchards. Larvae of D. livia were observed drilling fruits to eat seeds. At present, the life cycle of D. livia is poorly studied. We confirmed its identification using molecular tools and reported for the first time its occurrence in Southern of Tunisia.

Sirex noctilio is an invasive wood wasp pest in North America and in the southern hemisphere. Despite some reports on its presence in Tunisia, no further studies were undertaken on its distribution, hosts or potential associated parasitoids. In this paper, we confirmed the presence of S. noctilio in Tunisia, its widespread in several newly defined locations and its associated pine hosts. This species was widely distributed in the northern forests of Aleppo, maritime and stone pine and seemed to be absent in monospecific forests of Aleppo pine in semi-arid locations. The life cycle was completed within one year. Two parasitoid species emerged from S. noctilio-attacked logs which were identified as belonging to Ibalia and Rhyssa genera. Due to the apparent low abundance of S. noctilio and its absence in the semi-arid locations, risks of phytosanitary problems attributed to this species are of limited importance in Tunisian forests.

Carcina quercana is a polyphagous insect. In April 2018, larvae of C. quercana were observed for the first time in Majen Essef (north western Tunisia) on the strawberry tree (Arbutus unedo). To estimate the percentage of tree infestation, the number of infested trees among 40 trees found in an area of one hectare was counted. Branches of about 30 cm in length were cut and examined in the laboratory to determine the percentage of the infested leaves. On infested leaves, shelters were counted and the number of larvae by shelter was determined. The percentage of infested tree was 20% and that of infested leaves was 7.16%. In each leaf, we found between 1 and 3 shelters, in which only one larva host it. Larvae of C. quercana build their shelters of about 1.91 cm in length and 0.73 cm in width by means of silk.

Platypus cylindrus is the most important wood borer of cork oak trees (Quercus suber) in the Mediterranean Basin and namely Morocco, Algeria and Portugal where its presence has drastically increased in the past few decades. However, in Tunisia the insect does not cause relevant damages. The aim of this study was to determine the status of the insect in Tunisia and to understand the relationship between the beetle and its host plant, in order to establish a preventive control plan. During 2011, three sites were visited in the area of North-West of Tunisia, the most covered region with cork oak forests. Fifty trees were randomly sampled in each stand and their dendrometric and phytosanitary variables were recorded. The cork exploitation was also characterized by the observation of the debarking height and number of wounds caused by this practice. The intensity of attack by P. cylindrus was assessed using the parameter number of holes per tree. The analysis of the results showed that the insect presence is more related to the debarking parameters than to dendrometric and phytosanitary traits. The results of the present study may be useful to target P. cylindrus monitoring and to advise technical staff to improve the commonly used procedures for debarking cork oak trees.

At the beginning of April 2010, larvae of Orgyia trigotephras and Anacampsis scintillella caused severe plant defoliation in the region of Sejnane situated in the north of Tunisia. A. scintillella was observed on totally defoliated Halimium halimifolium plants. Larvae and pupae of A. scintillela were protected between two or three leaves of the host plant. Life history of A. scintillella is poorly studied, so far. In this paper, we presented a first report of this pest in Tunisia.

Operophtera brumata is a newly detected moth in Tunisia. It is considered the most important leaffeeding pest infesting fruit trees and deciduous forests in northern Europe. A recent outbreak of the winter moths was observed between 2009 and 2014 in oak forest in the North West of Tunisia with a peak density in 2010-2011. O. brumata was observed on totally defoliated Quercus canariensis and Q. afares. In this paper, we present a first report of this pest.

Erannis defoliaria, a spring-feeding moth, caused severe defoliation during springs 2009 and 2010. Larvae were collected from Quercus suber in northwestern forest of Tunisia: Bellif and Ain El Baya. Caterpillars of E. defoliaria were also observed feeding on Q. canariensis, Q. afares and other shrub species such as Pistacia lentiscus, Erica arborea, and E. multiflora. In this paper, we present a first report of this pest in Tunisia.

The pine sawyer beetle Monochamus galloprovincialis is one of the main vectors of the pathogenic pine wood nematode Bursaphelenchus xylophilus, the causal agent of pine wilt disease. Although the nematode is absent from northern Africa, the vector M. galloprovincialis has been previously reported in Morocco, Algeria and Tunisia. Despite these ancient reports, the insect´s distribution, hosts and biology are largely unknown for this part of the world. In this paper, we report on the presence of M. galloprovincialis in Tunisia, and record several new locations and the associated pine hosts, with brief notes on its emergence pattern. M. galloprovincialis was found to be widely distributed in Tunisia, being especially abundant on Aleppo and maritime pine forests. Insect was found to have a one-year life cycle, with the emergence pattern starting in the middle of May and prolonging until August, with a peak in June. This information will serve to develop a map intended to predict the risk of establishment and incidence of the pine wood nematode in Tunisia.