Search

The present paper highlighted the occurrence of Timarcha turbida (Erichson 1841) as an artichoke pest for the first time in Tunisian crops. In fact, Timarcha was never be reported previously to develop on a Compositae (Asteraceae) host plant. Here, larva and adult stages of the pest are described and host plants affinities in genus Timarcha are discussed. [ABSTRACT FROM AUTHOR]

Tomato production in geothermal greenhouses in Tunisia showed remarkable growth during the last decade and has been considered an important economic sector within the Tunisian agriculture. However, since 2010, this sector is constrained by the tomato leaf miner Tuta absoluta, which is considered one of the most destructive pests of tomato crops. The aim of this study was to evaluate the efficacy of the mating disruption with TUTATEC® in tomato crops in heated greenhouses. The efficacy of TUTATEC® at the theoretical doses of 55.5 and 111 g active ingredient of sex pheromone per hectare (300 and 600 dispensers/ha) to control T. absoluta was compared with mechanical control (manual deleafing) and conventional insecticides (Azadirachtin, 10 g/L and Cyantraniliprole, 100 g/L). The number of trapped males in water traps as well as the percentages of infested leaves and fruits were monitored weekly and compared with manual deleafing and insecticide-treated greenhouses. In greenhouses disrupted with 300 and 600 dispensers/ha, a reduction of 47.79 and 63.01% in male trap captures was observed, respectively, compared with mechanical control. The leaf damage was significantly lower in greenhouses disrupted with 600 dispensers/ha and insecticide treated greenhouses, with a reduction of infestation 29.53% and 32.02%, respectively. No significant differences were found in fruit damage between greenhouses disrupted with 300 and 600 dispensers/ha and the mechanical control. These results suggest that mating disruption is effective in the management of T. absoluta, and could be used in the framework of Integrated Pest Management strategies to control this pest. [ABSTRACT FROM AUTHOR]

Applying botanical extracts with potential insecticidal actvity has long been considered a promising eco-friendly alternative to the use of chemical insecticides. In the present study, we evaluated the contact toxicity of Mentha pulegium essential oil (applied at either 2.73 mg/L, 9.56 mg/L, 13.65 mg/L, 27.31 mg/L, or 40.96 mg/L) toward three pest scales, Planococcus citri, Aonidiella aurantii, and Chrysomphalus aonidum, and two chemical insecticides, chlorpyrifos (100 mL/hL) and spirotetramat (120 mL/hL), against P. citri and A. aurantii under laboratoty conditions. Toxicity of M. pulegium essential oil and both insecticides was also assessed on the coccinellid predator Cryptolaemus montrouzieri. The highest mortality rates for all scale insect nymphs (> 97% for A. aurantii and 100% for P. citri or C. aonidum) were obtained following essential oil application at a dose of 40.96 mg/L. Lowest mortality rate (3.6 ± 0.92%) of C. montrouzieri adults was induced by an essential oil application at a dose of 8.95 mg/L, compared to either dose 11.26 mg/L or 17.66 mg/L. Both chemical insecticides significantly affected survival of mealybug and armored scale insect nymphs until 21 days after treatment. Chlorpyrifos, being highly effective against P. citri and A. aurantii, was significantly more toxic than spirotetramat toward both A. aurantii nymphs and predatory C. montrouzieri adults until three weeks after treatment. Using M. pulegium essential oil in combination with spirotetramat could be recommended for eco-friendly, sustainable control of P. citri, A. aurantii and C. aonidum in citrus orchards while minimizing harmful side effects on C. montrouzieri. [ABSTRACT FROM AUTHOR]

Nanopesticides are novel formulations that can be applied against a wide range of insect pests as a sustainable alternative to less effective chemical pesticides. Here, acute toxicity of nano (abamectin-PLA-NS (1%) and abamectin-PLA-NS (0.1%)) and commercial formulations of abamectin was evaluated against the South American tomato pinworm, Tuta absoluta, in laboratory and open-field conditions in northeastern Tunisia. Additionally, side effects of nano and commercial formulations of abamectin were also investigated towards the two predatory mirids Macrolophus pygmaeus and Nesidiocoris tenuis either under laboratory or open-field conditions. Laboratory results of acute toxicity revealed no differences between the tested abamectin formulations (against T. absoluta larvae. LC50 values were 0.28, 0.23, and 0.23 for abamectin EC; 0.30, 0.18, and 0.18 for abamectin-PLA-NS (1%) and 0.57, 0.28, and 0.25 for abamectin-PLA- NS (0.1%) corresponding to three time intervals (24, 72 and 120 h after treatment). Abamectin EC, abamectin-PLA-NS (1%) and abamectin-PLA-NS (0.1%) applied at higher doses (0.6 mL/L and 1.2 mL/L) showed higher efficacy percentages (> 90%) in controlling T. absoluta larvae, fourteen days after treatment in open-field tomatoes. Commercial abamectin formulation showed higher toxicity toward M. pygmaeus adults and N. tenuis nymphs compared to nano formulations applied at the two aforementioned doses. High mortality rates, reaching 100%, were reported for M. pygmaeus adults exposed to 1 and 3 day-old residues for commercial formulation at 0.6 mL/L and 1.2 mL/L in laboratory conditions. However, in open-field tomatoes, low acute toxicity was induced by abamectin-PLA-NS (0.1%), ranging from 25 to 41.17%, compared to abamectin EC, ranging from 58.33 to 94.11%, and abamectin-PLA-NS (1%), ranging from 58.33 to 76.47%, at 0.6 mL/L against N. tenuis nymphs at apical leaves. For middle leaves, only abamectin-PLA-NS (0.1%) applied at 0.3 mL/L did not show significant toxicity against N. tenuis nymphs with low mortality level up to 7%, fourteen days after treatment. The practical implications of these results for enhancing integrated pest management programs of T. absoluta in tomatoes are discussed herein. [ABSTRACT FROM AUTHOR]

Gortyna xanthenes (Germar) and Depressaria erinaceella (Staudinger) are key pests of artichoke in Tunisia causing major losses. To this end, a 2-year field survey was carried out in order to assess possible damage caused by these two pests. The results showed that serious attacks were found on artichoke flower heads ranging from 17 to 26% and from 7 to 10% for D. erinaceella and G. xanthenes, respectively. On stems, damages caused by G. xanthenes may exceed 60%. Measures of the length of the larva and the width of head capsule in the laboratory showed the presence of six and seven instar larvae for G. xanthenes and D. erinaceella, respectively. These results could be very useful to develop effective management tools against artichoke pests in Tunisia. [ABSTRACT FROM AUTHOR]

Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), a pinworm native to South America, has invaded Tunisia, as well as the whole African continent, since 2008 inducing severe crop damages and substantial economic losses in all tomato-producing areas. During the last decade, several research studies and management efforts have been performed in an attempt to find out the most effective and sustainable pest control options against this devastating pest. Herein we explore, comprehensively summarize and discuss the most up-to-date state of scientific knowledge regarding bio-ecological aspects of the pest, its indigenous natural enemies and all categories of management strategies adopted so far against this economic pest in Tunisia. [ABSTRACT FROM AUTHOR]

Since its first detection in Tunisia in 2008, the tomato pinworm, Tuta absoluta, has become a serious problem to tomato crops by causing heavy yield losses. The aim of this work was to evaluate the efficacy of some actives ingredients, commonly used by Tunisian farmers, under laboratory and greenhouse conditions in controlling T. absoluta larvae. We also tested the role of mass trapping as control method for T. absoluta while performing two greenhouse trials: one to test the most effective number of pheromone traps to be used and the second evaluating the combination of insecticides and pheromone traps. Our study demonstrated that the product combining abamectin and chlorantraniliprole was the most effective 2 h after the treatment in laboratory trials. Moreover, this study indicated that the dose of two sex pheromone traps/greenhouse was the most effective compared to the other tested dose. Also, mass trapping alone (2 sex pheromone traps/greenhouse) was not effective in reducing larval populations: flubendiamid and cyromazin caused 96 and 77% larval mortality, respectively. [ABSTRACT FROM AUTHOR]

The mating disruption technique using Checkmate® VMB-XL pheromone dispensers, in combination with imidacloprid-based insecticide treatments through drip irrigation, was tested against vine mealybug in Tunisian vineyards for the first time in the South Mediterranean area. The number of male vine mealybugs caught in traps of mating disruption (MD) plots was significantly lower than that of Non-MD plots, indicating that the application of Checkmate® VMB-XL significantly disrupted the male-female vine mealybug sexual communication. The cumulative effect of mating disruption on vine mealybug over time reached 120 days. Two months after Checkmate® VMB-XL application, the density of mealybug nymphs and adult females on grapevine basal leaves was significantly reduced in all MD plots. The obtained results provide evidence that the application of Checkmate VMB-XL under Center-South Tunisian vineyard conditions proved to be very effective in confusing vine mealybug males and disrupting the mating process. The eventual future use of this technique in Integrated Pest Management programs in Tunisia is discussed herein. [ABSTRACT FROM AUTHOR]

Control of the invasive vine mealybug Planococcus ficus (Signoret) can be achieved through integration of different management strategies such as the application of chemical treatments and biological control. However, compatibility between these control methods is considered crucial when adopting integrated pest management (IPM) programs against this insect pest. The recently used insecticides Prev-Am®, a contact biopesticide, and spirotetramat, a systemic tetramic acid insecticide, were assessed in laboratory conditions for their side effects on the vine mealybug parasitoid Anagyrus sp. near pseudococci with reference to chlorpyriphos-methyl, an organophosphate insecticide conventionally used for mealybug control in vineyards. Regarding contact toxicity, chlorpyriphos-methyl caused 100% parasitoid mortality 24 h after treatment, but parasitoid mortality from Prev-Am® or spirotetramat was almost absent. Neither the total parasitoid offspring/female nor the sex ratio of the progeny was negatively affected by Prev-Am® or spirotetramat relative to the untreated control. According to the IOBC classification for laboratory trials, both Prev-Am® and spirotetramat were rated harmless (IOBC category 1), whereas chlorpyriphos-methyl was categorized as harmful (IOBC category 4) to A. sp. near pseudococci. None of the insecticides adversely affected the development of the parasitoid pupal stage inside mealybug mummies or the survival of the emerged parasitoids. The practical implications of the results for implementing mealybug IPM programs in vineyards are emphasized and discussed. [ABSTRACT FROM AUTHOR]

Reports that eotetranychus pruni was recorded in Belgian and Tunisian apple orchards for the first time. The aim of this study was to compare a Belgian (Vieusart) and a Tunisian strain (Grombalia), with respect to their life history and demographic traits. Furthermore, a Tunisian strain of Tetranychus urticae (Sousse) was also added to the study, in order to evaluate the potential status of the Tunisian strain of E. pruni. Experiments were carried out in the laboratory (24 °C) on apple leaf discs. Significant differences were noticed between the two species, with respect to development time (males), fecundity and fertility (egg hatching), but no differences could be detected between the two strains of E. pruni. Life tables were set up to describe the population statistics. The calculated intrinsic rates of natural increase (r[subm]) appear to be rather low per se and do not correspond to those of typical ?r strategic pests?. The Bootstrap procedure allows us to estimate the confidence interval for these r[subm] values. By using this method, the two Tunisian strains (T. urticae and E. pruni) appear to be quite similar, and contrast with the Belgian strain (E. pruni). The potential pest status of the Tunisian strain of E. pruni is discussed.

The names of the varieties cultivated in the two study regions were given wrongly in the Materials and Methods section. The correct names are as follows. [ABSTRACT FROM AUTHOR]

Synthetic chemicals are extensively used to limit the substantial crop damage induced by two closely related scale insects, the vine mealybug Planococcus ficus (Signoret) and the citrus mealybug Planococcus citri Risso (Hemiptera: Pseudococcidae). Both organisms are economically important pests occurring in vineyards and/or in citrus orchards worldwide. Synthetic chemicals can be either incorporated in pesticides aimed at directly controlling these pests or used as semiochemicals (i.e., sex pheromones) for monitoring, mass trapping, mating disruption, and/or for kairomonal attraction to enhance parasitoid performances. Growing evidence of both an alarming bee decline and destruction of auxiliary fauna driven by pesticides have stimulated an urgent need for in-depth research clarifying the adverse side effects of pesticides on beneficial arthropods. We have reviewed the current knowledge on mealybug pest control based on insecticides and semiochemicals. We highlight the following major advances: (1) How the active substances of insecticides (four organophosphates, imidacloprid, buprofezin, and spirotetramat) affect target and non-target organisms, (2) in which contexts and how a semiochemical-based strategy could be applied to deal with serious mealybug infestations, and (3) the implications of the appropriate exploitation of these synthetic chemicals for sustainable development. Using selective insecticides with novel modes of action and long-lasting efficacy in combination with eco-friendly semiochemical-based tools is a promising strategy for developing sustainable integrated pest management programs. This would help to maintain biodiversity dynamics and vital ecosystem services, thereby sustaining crop yields. [ABSTRACT FROM AUTHOR]