The tomato leafminer Tuta absoluta (Meyrick) in Tunisia: current status and management strategies

The tomato leafminer Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) was first identified in the region of Akkouda in October 2008 before it spread to all tomato‐producing areas in Tunisia. The introduction of this pest disturbed existing pest control programmes in greenhouses and open fields, forcing Tunisian growers to use more chemicals to reduce its impact on their crops. A national programme was adopted to control T. absoluta, including cultural practices, the use of pheromones, the installation of insect‐proof screens in greenhouses, and the use of organic insecticides including Bacillus thuringiensis Kurstaki (Bt) and plant extract‐based products. In addition, a few experiments in biological control, using the predatory Mirid Nesidiocoris tenuis Reuter (Heteroptera: Miridae) and the parasitoid wasp Trichogramma cacoeciae Marchal (Hymenoptera: Trichogrammatidae), were conducted in greenhouses and open‐field crops (producing tomatoes for fresh consumption as well as for processing). This paper describes the status of T. absoluta in Tunisia, including data collected from sex pheromone traps installed in six tomato‐producing areas (Takelssa, Korba, Teboulba, Bekalta, Sousse and Kairouan) between 2009 and 2011, and control strategies in greenhouses and open fields.     

First record of Bregmatothrips dimorphus (Priesner, 1919) (Thysanoptera: Thripidae) in Tunisia

During an inventory study of thrips species carried out in the central‐eastern coastal region of Tunisia in 2010 and 2011, Bregmatothrips dimorphus (Priesner, 1919) (Thysanoptera; Thripidae) was found on two host plants; barley (Hordeum vulgare Linnaeus) and sorghum (Sorghum bicolor Moench). This is the first record of B. dimorphus in Tunisia. Its distribution in other parts of the world and taxonomic characteristics are briefly presented.     

The pumpkin fly Dacus frontalis (Diptera: Tephritidae): a new pest of curcubits in Tunisia

The pumpkin fly Dacus frontalis is reported in this paper for the first time in Tunisia, where it was found in several locations. It is a pest of cucurbits of economic importance and is common especially in the eastern and southern parts of Africa. D. frontalis was collected from infested cucumber fruits in the region of El‐Jebil (Kairouan) and female bait traps for the Mediterranean fruit fly Ceratitis capitata and the olive fly Bactrocera oleae. Preliminary data from Tunisia suggest that D. frontalis is already established in four regions in which cucurbits are important crops. Brief notes on the diagnostic features for the species, its ecology and geographic distribution are given. Symptoms on cucumber from Tunisia are presented.     

Effects of nymphal density (Bactericera trigonica) and feeding on photosynthetic pigments,proline content and phenolic compounds in carrot plants

European Journal of Plant Pathology - Insect feeding induces physiological and biochemical changes in host plants. Indeed, symptom severity often depends on insect density. Recently, the carrot...     

The black fig fly Silba adipata (Diptera: Lonchaeidae) as an emerging pest in Tunisia: preliminary data on geographic distribution,bioecology and damage

Phytoparasitica - Frugivorous fruit flies are considered among the most damaging pests of cultivated fruit crops. The most studied ones are those belonging to the Tephritidae family such as the...     

Establishment and dispersal of the parasitoids Ageniaspis citricola Logvinovskaya (Hymenoptera: Encyrtidae) and Semielacher petiolatus Girault (Hymenoptera: Eulophidae), introduced into Tunisia for the biological control of Phyllocnistis citrella (Lepidoptera: Gracillariidae)

Abstract

A programme for the biological control of the citrus leafminer Phyllocnistis citrella Stainton (Lepidoptera, Gracillariidae) was carried out in Tunisia between 1996 and 1998. Two exotic parasitoids, Ageniaspis citricola (Logvinovskaya) (Hymenoptera, Encyrtidae) and Semielacher petiolatus Girault (Hymenoptera, Eulophidae), were introduced from Australia, mass-reared in a greenhouse on Citrus aurantium L. seedlings infested with P. citrella, and released in different orchards located in the major citrus-growing area of Tunisia. In 1996, A. citricola was recovered in 39.13% of release sites, reaching a maximum percentage of parasitism of 28%. In 1997, the parasitoid was recovered in a third of all release points, with an average percentage of parasitism of 5%. However, the wasp was unable to survive the winter 1998, and has become extinct. The non-establishment of A. citricola may have been due to the more arid climatic conditions present during the rainless summer and most of the autumn in Tunisia. By contrast, the establishment, dispersal, and reduction in citrus leafminer population observed with S. petiolatus between 1997 and 1998 shows this species to be well-adapted to the Tunisian climate. The average percentage parasitism of P. citrella by S. petiolatus increased from 6.6% in 1997 to 15% in 1998. Moreover, S. petiolatus was established in 76% of release points in 1997 and in 82% in 1998. It spread as much as 30 km from some release points, with no apparent decline in parasitism levels with distance. Semielacher petiolatus is considered to be an effective biological control of the leafminer in Tunisia. Its biological control action would supplement the action of the native parasitoids Pnigalio sp. and Cirrospilus pictus Nees (Hymenoptera, Eulophidae).     

Response of the tomato miner Tuta absoluta (Lepidoptera: Gelechiidae) to thirteen insecticides in semi‐natural conditions in Tunisia

Experiments on larvicide and ovicide activity of 13 insecticides in semi‐natural conditions showed a medium to low efficacy of bio‐insecticides on all instars of Tuta absoluta (Meyrick) except for Bacillus thuringiensis Berliner var. kurstaki which was distinguished by an average mortality of 72.5%. Spinosad and Spinetoram based insecticides showed high efficiency in controlling all instars of larvae with respectively an average mortality of 66.5% and 85.6%. However, this study revealed a unique ovicide effect of azadirachtin‐neem oil based insecticide with 43.8% egg mortality.     

Evaluation of two methods for the protection of tomato crops against the tomato leafminer Tuta absoluta (Meyrick) under greenhouses in Tunisia

The evaluation of two methods of plant protection in tomato crops cultivated in greenhouses against Tuta absoluta (Meyrick) in the region of Teboulba in Tunisia was performed. This study evaluated the use of insect‐proof screens alone or in combination with one sex pheromone water trap compared to a control greenhouse not equipped with either. The study confirms that the use of one sex pheromone water trap combined with insect‐proof covering of doors and aeration openings is sufficient to guarantee good crop protection. This combined control system allowed a low density of the pest (less than 2 individuals per leaf) to be maintained and a mean number of mines below 1 mine per leaf.     

First record of black vine thrips,Retithrips syriacus Mayet,in Tunisia

During a study on thrips species carried out in Tunisia during 2009 and 2010, Retithrips syriacus was encountered in two different sites and on two host plants: grapevine (Vitis vinifera) and persimmon (Dyospiros kaki). This species is recorded for the first time in Tunisia and the western part of North Africa. Brief information about its worldwide distribution and morphology is presented.     

The pomegranate butterfly Deudorix livia (Lepidoptera: Lycaenidae): an emerging pest on dates in Tunisia

The pomegranate butterfly Deudorix (=Virachola) livia Klug 1834 (Lepidoptera: Lycaenidae) was encountered for the first time infesting dates (Phoenix dactylifera, variety Deglet Nour) in the oasis of Gafsa, Southern Tunisia in September 2011. Larvae of D. livia only caused damage on date fruits at the phenological stages kimiri (green fruits) and khalal (yellow fruits). The average infestation rate of dates was 10%. In addition, 7.1% of the infested fruits dropped to the ground. Damage caused by this insect on dates is described, the current situation in Tunisia is provided and possible control methods in Tunisia are briefly discussed. Although this pest has previously been reported in Tunisia on pomegranate this is the first report of D. livia on dates in the country.