The most distinctive morphogenetic feature of leaves is their being either simple or compound. To study the basis for this dichotomy, we have exploited the maize homeobox-containing Knotted-1 (Kn1) gene in conjunction with mutations that alter the tomato compound leaf. We show that misexpression of Kn1 confers different phenotypes on simple and compound leaves. Up to 2000 leaflets, organized in...

The leafminer Tuta absoluta (Meyrick) is a major pest of the tomato crop and its development rate is known to decline when nitrogen availability for crop growth is limited. Because N limitation reduces plant primary metabolism but enhances secondary metabolism, one can infer that the slow larval development arises from lower leaf nutritive value and/or higher plant defence. As an attempt to stu...

Field studies were conducted on the application of Leucaena leucocephala leaf extracts as an alternative to carbofuran a synthetic nematicide, while possible residues in tomato fruits also analysed. Acetone, methanol and petroleum ether fractions leaves L. applied at 200 mg/mL variants 100 mL, 150 mL naturally nematode infested field. Comparison was made with insecticide nematicide. Samples fro...

Biweekly field visits starting from January to the end of April 2011 were conducted to tomato fields (open and plastic houses) heavily infested with the tomato borer Tuta absoluta, in order to survey natural enemies associated with this pest. Three hemipterans were found: Orius albidipennis, Orius sp. (Anthocoridae) and Nesidiocoris tenuis (Miridae). In addition, the parasitic wasp Bracon (Habr...

Gene array technology was applied to tomato as a model system to examine plant physiological response to silverleaf whitefly (SLW), Bemisia argentifolii (a.k.a. Bemisia tabaci biotype B) feeding. Our objective was to study gene expression in tomato plants subjected to a moderate infestation of whitefly. Plants were destructively harvested 25 days after infestation and samples of old and young l...

Solid CO (dry ice) was added to pots containing soil that was infested either with eggs of the root-knot nematode, Meloidogyne incognita, or with tomato (Lycopersicon esculentum 'Rutgers') root fragments that were infected with various stages of the nematode. Two hours after dry ice was added, thermocouples in the soil recorded temperatures ranging from -15 degrees C to -59 degrees C. One day a...

Class 1 KNOTTED1-LIKE HOMEOBOX (KNOXI) genes encode transcription factors that are expressed in the shoot apical meristem (SAM) and are essential for SAM maintenance. In some species with compound leaves, including tomato (Solanum lycopersicum), KNOXI genes are also expressed during leaf development and affect leaf morphology. To dissect the role of KNOXI proteins in leaf patterning, we express...

The whitefly, Bemisia tabaci biotype B, has been shown to cause pathogenesis-related (PR) proteins to accumulate in plants as a result of direct feeding, but their specific role in plant defensive systems is unclear. Our objective was to compare accumulation of tomato PR proteins (beta-1,3-glucanase, chitinase, peroxidase, P2 and P4) in response to whitefly, with or without tomato mottle virus ...

effects of water stress and fusarium oxysporum f. sp. lycoperseci (fol) on the growth of tomatoes were studied in a greenhouse experiment. treatments consisted of five levels of water stress (1, 3, 5, 7 and 9 day irrigation intervals). infested soil consisting of 400 chlamydospores g1 of fol and non infested soil were used. experiments arranged in a completely randomized design with 8 replicati...