Insecticide Effect of Zeolites on the Tomato Leafminer Tuta absoluta (Lepidoptera: Gelechiidae).

(1) Background: The tomato leafminer Tuta absoluta (Lepidoptera: Gelechiidae) is a key tomato insect pest. At present, it is considered to be a serious threat in various countries in Europe, North Africa, and Middle East. The extensive use and the developed resistance of T. absoluta to spinosad causes some concern, which leads to the need for alternative products. (2) Materials and Methods: Several laboratory experiments were conducted to investigate the ovicidal properties of a zeolite particle film on T. absoluta. The toxicity of three different zeolites and six zeolite formulations to T. absoluta eggs and larvae was determined using different exposure methods. (3) Results: In general, the formulated zeolites yielded higher egg and larvae mortality values, especially when the zeolite particle film was residually applied. Notable differences in mortality rates from exposure to zeolites compared to other products, such as kaolin, its formulated product Surround, and the insecticide spinosad, were observed. Kaolin and Surround exhibited little or no effect for both application methods, while the hatch rate was reduced by 95% when spinosad was applied topically. Spinosad yielded egg and larvae mortality rates of 100% for both application methods. Additionally, increased oviposition activity was observed in adults exposed to the wettable powder (WP) formulations. These WP formulations increased egg deposition, while Surround and spinosad elicited a negative oviposition response. (4) Conclusions: It can be derived that the tested products, zeolites BEA (Beta polymorph A), FAU (Faujasite), LTA (Linde type A), and their formulations, had no real insecticidal activity against the eggs of T. absoluta. Nevertheless, egg exposure to zeolites seemed to affect the development process by weakening the first instar larvae and increasing their mortality. Subsequently, based on the choice test, no significant difference was observed between the number of eggs laid on the treated leaves and control leaves.

High population densities of Macrolophus pygmaeus on tomato plants can cause economic fruit damage: interaction with Pepino mosaic virus?

BACKGROUND: The zoophytophagous predator Macrolophus pygmaeus Rambur (Hemiptera: Miridae) is a successful biocontrol agent against several pest species in protected tomato crops. This predator is considered to be harmless for the crop. However, in recent years, Heteroptera feeding punctures on tomato fruit in Belgian and Dutch greenhouses have been misinterpreted as Pepino mosaic virus (PepMV) symptoms. In this study, three hypotheses were tested: (1) M. pygmaeus causes fruit damage that increases with population density and surpasses economic thresholds; (2) the presence of prey or alternative prey reduces the damage; (3) an infection of the tomato plants by PepMV triggers or aggravates M. pygmaeus fruit damage. RESULTS: At increasing M. pygmaeus densities, the severity of fruit damage increased from a few dimples towards yellowish discoloration and deformed fruits. A correlation with an infection with PepMV was found. The severity of the symptoms was independent of the presence of prey. A minimum economic density threshold was estimated at 0.32 M. pygmaeus per leaf. CONCLUSION: M. pygmaeus can cause economic damage to tomato fruits at densities common in practice. An infection of the plants with PepMV enhances fruit symptoms significantly. Interacting plant defence responses are most likely the key to explaining this, although confirmation is required. © 2015 Society of Chemical Industry.

Efficacy of entomopathogenic nematodes against larvae of Tuta absoluta in the laboratory.

BACKGROUND: Previous studies have indicated the control potential of entomopathogenic nematodes (EPNs) against Tuta absoluta. Here, the potential of Steinernema feltiae, S. carpocapsae and Heterorhabditis bacteriophora is studied when applied against larvae of T. absoluta inside leaf mines in tomato leaf discs by means of an automated spray boom. RESULTS: The studied EPN species were effective against all four larval instars of T. absoluta but caused higher mortality in the later instars (e.g. fourth instar: 77.1-97.4% mortality) than in the first instars (36.8-60.0% mortality). Overall, S. feltiae and S. carpocapsae yielded better results than H. bacteriophora. Steinernema carpocapsae and H. bacteriophora performed better at 25 °C (causing 55.3 and 97.4% mortality respectively) than at 18 °C (causing 12.5 and 34.2% mortality respectively), whereas S. feltiae caused 100% mortality at both temperatures. Under optimal spraying conditions and with the use of Addit and Silwet L-77 adjuvants, a reduced dosage of 6.8 infective juveniles (IJs) cm(-2) yielded equally good control as a recommended dosage of 27.3 IJs cm(-2) . CONCLUSION: Under laboratory conditions, S. feltiae and S. carpocapsae showed good potential against the larvae of T. absoluta inside tomato leaf mines. Results need to be confirmed in greenhouse experiments. © 2015 Society of Chemical Industry.

The GCP molecular marker toolkit, an instrument for use in breeding food security crops.

Crop genetic resources carry variation useful for overcoming the challenges of modern agriculture. Molecular markers can facilitate the selection of agronomically important traits. The pervasiveness of genomics research has led to an overwhelming number of publications and databases, which are, nevertheless, scattered and hence often difficult for plant breeders to access, particularly those in developing countries. This situation separates them from developed countries, which have better endowed programs for developing varieties. To close this growing knowledge gap, we conducted an intensive literature review and consulted with more than 150 crop experts on the use of molecular markers in the breeding program of 19 food security crops. The result was a list of effectively used and highly reproducible sequence tagged site (STS), simple sequence repeat (SSR), single nucleotide polymorphism (SNP), and sequence characterized amplified region (SCAR) markers. However, only 12 food crops had molecular markers suitable for improvement. That is, marker-assisted selection is not yet used for Musa spp., coconut, lentils, millets, pigeonpea, sweet potato, and yam. For the other 12 crops, 214 molecular markers were found to be effectively used in association with 74 different traits. Results were compiled as the GCP Molecular Marker Toolkit, a free online tool that aims to promote the adoption of molecular approaches in breeding activities.