Evaluation of the effectiveness of Neoseiulus cucumeris (Oudemans) as a predator of Tuta absoluta (Meyrick)

The leaf miner, Tuta absoluta is continue to be a serious threat to solanaceous plants, especially tomato plant worldwide. Tomato crop in Saudi Arabia has been recently affected by T. absoluta, which is difficult to control due to its unique biological features, such as high fecundity and its potential to develop resistance to chemical pesticides. In this article, the suitability and effectiveness of the predatory mite, Neoseiulus cucumeris (Oudemans) (Acari: Phytoseiidae), an indigenous species usually found in tomato greenhouses of northcentral Saudi Arabia, has been evaluated on eggs and 1st instar larvae of T. absoluta in the laboratory. All experiments were conducted in an incubator at three constant temperatures of 22, 27 and 32°C ± 1°C, 50 ± 4% R.H. and L12:D12 h photoperiod. Adult females and males of N. cucumeris were able to feed and sustain oviposition on eggs and 1st instar larvae of T. absoluta, and could be an effective biocontrol agent against T. absoluta. The N. cucumeris had a clear preference for eggs compared to 1st instar larvae of T. absoluta. The results showed the obvious effect of the temperature on the consumption rate of the predatory mite. The maximum daily consumption rate occurred during the oviposition period, when the females of the predatory mite consumed an average of 4.26 eggs and 2.44 1st instar larvae of T. absoluta. In general, total fecundity was high with T. absoluta eggs as a food source when temperature increased from 22 to 32°C. The highest fecundity rate (42.92 and 20.97 eggs /female) was recorded at 32°C, while the lowest one (26.77 and 10.12 eggs / female) was recorded at 22°C, when N. cucumeris female fed on eggs and 1st instar larvae of T. absoluta, respectively. The results of this study indicated that the predatory mite, N. cucumeris can be considered a promising potential candidate for controlling the leaf miner T. absoluta, and further research is required to assess its effectiveness under greenhouse conditions.

MONITORING AND CONTROL OF THE PEST TUTA ABSOLUTA (MEYRICK) IN TOMATO CROPS UNDER HIGH PLASTIC TUNNELS

Tuta absoluta – tomato leafminer (Meyrick) (Lepidoptera: Gelechiidae) is a major pest of tomato crops in protected areas, which attacks both foliage and fruit, in all phases of plant growth. Its invasion has led to yield and quality decrease, increased costs to control and high dependence on chemical insecticides. With pheromone traps it is possible to monitor and reduce the density of the pest population. The experience was established in 2020, at a farmer in Dobreni village (Giurgiu county). In the first and second crop cycle, the population of the pest Tuta absoluta was monitored, by placing Delta pheromone traps in tomato crops. The Sahmat F1 tomato hybrid was planted in both crop cycles. Pest monitoring was performed weekly, by changing the adhesive plates with pheromones from Delta traps, on the dates: 03.06, 10.06, 17.06, 24.06, 01.07, 08.07, 15.07, 22.07 in the first cycle of crop and on the dates: 29.07, 05.08, 12.08, 19.08, 02.09 , 09.09, 16.09, 23.09 in the second cycle. The appearance and evolution of the attack were recorded in the both crop cycles and its influence on production was established.

First record in Africa of the parasitoid Dolichogenidea gelechiidivoris (Hymenoptera: Braconidae) on tomato leafminer Tuta absoluta (Lepidoptera: Gelechiidae) from tomato fields in Algeria

The Neotropical parasitoid wasp Dolichogenidea gelechiidivoris (Marsh, 1975) (Hymenoptera: Braconidae), one of the most important biocontrol agents of the South American tomato pinworm Tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae), is reported for the first time from Africa, from tomato grown in open fields and greenhouses in several regions of Algeria. Color photos of specimens from Algeria, Spain and South America, as well as the holotype and one paratype are provided. Morphological and molecular details to better characterize and recognize the species are also provided. We speculate that D. gelechiidivoris arrived accidentally to Algeria from Spain, where it has recently been reported. The consequences for future biocontrol projects against T. absoluta in Africa are discussed.

Knowledge, Attitude, and Practices on Tomato Leaf Miner, Tuta absoluta on Tomato and Potential Demand for Integrated Pest Management among Smallholder Farmers in Kenya and Uganda

Agricultural growth and food security are a priority in many developing countries. This has led to increased attention to effective pest management. Integrated Pest Management (IPM) strategy is a sustainable and recommended alternative to the use of synthetic pesticides in the management of tomato pests, with Tuta absoluta being the major one. This study seeks to assess the awareness, attitude, and control practices on T. absoluta and examine the potential adoption of a proposed IPM strategy for the management of a pest using a randomly selected sample of 316 and 345 tomato growing households in Kenya and Uganda, respectively. The study findings indicate that T. absoluta is the major pest affecting tomato production, with most farmers using synthetic pesticides to manage it. Furthermore, we find a significant proportion of the survey respondents willing to adopt the IPM strategy. The probability of adopting the strategy was positively related to a farmer being male, residing near a source of inputs, accessing training, and possessing good knowledge, attitude, and practices towards the use of non-pesticides strategies. Thus, training, promotion, and awareness creation of the T. absoluta IPM are recommended for the sustainable management of the pest in tomato production.

Insights on solanaceous resistance against tomato leafminer (Tuta absoluta), with emphasis on chemical compounds useful in integrated pest management

For integrated pest management (IPM) and organic farming, breeding resistant varieties is one of the most eco-friendly approaches, that goes along botanicals and other different cultural practices, as the use of companion plants. Among the many pest species that invaded the whole world in the last decades, one of the most frightening is the tomato leafminer, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), a devastating pest of cultivated tomato worldwide. Tomato is one of the most important agricultural commodities, including the main mean of subsistence in many countries from Africa and middle East. As chemical pesticides failed to control de pest spread and led to many reports of resistant populations, alternative methods for tomato leafminer management must be quickly developed. Many of such alternatives count on a wide range of chemical compounds. The chemical compounds most often responsible for “constitutive resistance”, synthetized by tomato are methyl-ketones (2-tridecanone), sesquiterpenes (zingiberene), and acyl sugars (acylglucose and acylsucrose) while the chemical compounds produced by other plants, used as isolated substances or mixtures, which have antifeedant, growth inhibiting, repellent, and insecticide effects, are azadirachtin, carvacrol, cinnamaldehyde, citronellal, eugenol, linalool, nicotine, pyrethrin, rotenone, thujone, thymol, α-terpineol, 1.8-cineol, etc. Many of them are already commercially available but their efficacy and use differ widely. Therefore, a deeper understanding of the resistance mechanism of solanaceous species related to chemical compounds and substances important for IPM plans developed against T. absoluta is required by the breeding programs.

Temperature-dependent modelling and spatial prediction reveal suitable geographical areas for deployment of two Metarhizium anisopliae isolates for Tuta absoluta management

Tuta absoluta is one of the most devastating pests of Solanaceae crops in Africa. We previously demonstrated the efficacy of Metarhizium anisopliae isolates ICIPE 18, ICIPE 20 and ICIPE 665 against adult T. absoluta. However, adequate strain selection and accurate spatial prediction are fundamental to optimize their efficacy and formulations before field deployment. This study therefore assessed the thermotolerance, conidial yield and virulence (between 15 and 35 °C) of these potent isolates. Over 90% of conidia germinated at 20, 25 and 30 °C while no germination occurred at 15 °C. Growth of the three isolates occurred at all temperatures, but was slower at 15, 33 and 35 °C as compared to 20, 25 and 30 °C. Optimum temperatures for mycelial growth and spore production were 30 and 25 °C, respectively. Furthermore, ICIPE 18 produced higher amount of spores than ICIPE 20 and ICIPE 665. The highest mortality occurred at 30 °C for all the three isolates, while the LT50 values of ICIPE 18 and ICIPE 20 were significantly lower at 25 and 30 °C compared to those of ICIPE 665. Subsequently, several nonlinear equations were fitted to the mortality data to model the virulence of ICIPE 18 and ICIPE 20 against adult T. absoluta using the Entomopathogenic Fungi Application (EPFA) software. Spatial prediction revealed suitable locations for ICIPE 18 and ICIPE 20 deployment against T. absoluta in Kenya, Tanzania and Uganda. Our findings suggest that ICIPE 18 and ICIPE 20 could be considered as effective candidate biopesticides for an improved T. absoluta management based on temperature and location-specific approach.

Susceptibility Assessment of Two Tomato Hybrids Against Tuta absoluta Infestation Under Greenhouse Conditions

Abdel-Razek, A.S., N.M. Abd El-Ghany, M.A. Gesraha, T.A. Elewa and A. Moussa. 2021. Susceptibility Assessment of Two Tomato Hybrids Against Tuta absoluta Infestation Under Greenhouse Conditions. Arab Journal of Plant Protection, 39(4): 317-322. https://doi.org/10.22268/AJPP-39.4.317322 Tuta absoluta is a major insect pest which attack tomato plant varieties in Egypt. Several control attempts were carried out to avoid major crop losses by heavy application of chemical insecticides. The aim of the present study is to assess the susceptibility of infestation of T. absoluta of two tomato varieties (Shifa and Savera F1 hybrids) under greenhouse conditions. The tomato varieties were planted in two plantation periods at the district of Kom Hamada, El-Nubaria province, El-Behira Governorate. The susceptibility tests were done by random counting of leaf samples for the presence of T. absoluta mines and larvae. Both tomato varieties showed almost the same T. absoluta infestation level. Moreover, yield assessment was carried out for the two plantation periods by taking the average fruit weight yield (Kg/acre). The tomato yield results showed that Savera F1 hybrid tomato had higher yield compared to Shifa F1 hybrid variety, but such difference was not significant, However, the yield difference of both vireties between the two planting dates was significant. Keywords: Tomato, Tuta absoluta, susceptibility, leaf-mine, larvae, yield.