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• Influence of pesticide use on flower formation and fertility of some fruit species

  103-106

  I. J. Holb

  Views:

  283

  This review evaluated previous studies on the effect of pesticide use on flower formation and fertility of some fruit species. The study was divided into two parts. First part of the overview will evaluate the most commonly used fungicides on pollen toxicity and their germination ability under fungicide exposure on different fruit species. Effect of fungicides on fruit set was also critically reviewed. Second part of the study summarised those few studies which determined the effect of some insecticides and acaricides on flower formation and fertility.

• Some microbial treatments against the tomato leaf miner; Tuta absoluta (Merick) under natural field conditions

  81-84.

  Mohammed Amira S.

  El-Khatteeb Nagwa M. M.

  A. Ezzat

  Views:

  202

  In an attempt to find more effective methods and safety to control the tomato leaf miner, Tuta absoluta, this research was conducted to study the efficacy of the four bio-treatments ; two bacterial isolates (Bacillus subtilis. and Pseudomonas Fluorescence), one fungal isolate Trichoderma viride) and Spinosad as a microbial insecticide compared with the most common insecticides used against the dipterous and lepidopterous leaf miners in Egypt; Profenofos and Aphox. In the two successive seasons; 2011 and 2012, the fungal isolate Trichoderma viride achieved the lowest infestation(numbers of infested leaflets, mines, infestation percentages) which were 167, 195, and 21.9% resp.in season 2011 and 198, 222 and 26.2% resp. in season 2012. While the highest infestation was occurred in case of using the insecticides, Aphox (423, 559 and 55.9% resp.& 384, 839 and 72.2%. and Prohpenofos (436, 562 and 57.7% &391, 534 and 51.7% resp.).during 2011 and 2012 respectively. The other treatments occupied the intermediate levels. On the other hand, the yield of tomato fruits was increased by 75% over the check in case of plants treated with Trichoderma viride isolate, but the pesticide treatment given weak or no impact in increasing tomato crop. In season 2012, the infested tomato fruits percentages with T. absoluta larvae and Rhizoctonia soil rot disease(that Frequently observed incidentally) were recorded the minimum levels obtained by spraying Trichoderma viride isolate(21.38 and 10.32% resp.). In contrast, the maximum levels were recorded in Prophenofos (44.87 and22.78% resp.) and Aphox treatments(47.22 and 27.78% resp.).

• Phytoplasma diseases of grapevine and the possible measures to control them

  37-43.

  M. Kölber

  Views:

  341

  Phytoplasmas are a special group of phloem-living pathogens in several plant species. Grapevine yellows (GY) is a term for phytoplasma diseases occurring on Vitis vinifera and inducing the same or very similar symptoms and causing severe losses worldwide. Flavescence Dorée (16SrV) phytoplasma (FD, species name: ‘Candidatus Phytoplasma vitis’) is considered a quarantine pest in several countries due to its epidemic character and high economic loss it provokes. The leafhopper Scaphoideus titanus is the univoltine and monophagous vector of FD. Bois noir disease caused by stolbur (16SrXII-A) phytoplasma (species name: ‘Candidatus Phytoplasma solani’) is described under different disease names in different countries. Hyalesthes obsoletus (Cixiidae) is the only proved polyphagous vector of BN. However, distribution of BN disease is increasing also on those areas where H. obsoletus is not prevalent or only in a very low number. Therefore the presence of other vectors cannot be concluded. The ‘Tuf-a’ type Stolbur phytoplasma is associated with stinging nettle (Urtica dioica) and the tuf-b type one to field bindweed (Convolvulus arvensis). There are only preventive control measures against phytoplasmas: the use of pathogen-free propagating material, hot water treatment of propagating material, as well as control of vectors and weeds. S. titanus can be efficiently controlled by insecticide treatments. However, in case of H. obsoletus, insecticides are not effective due to the biological characters and feeding habits of the vector.Weed control can reduce H. obsoletus specimen and their abundance to a certain extent. Extensive research is needed on wild hosts of GY phytoplasmas especially on BN phytoplasma and its vectors to the better understanding of their epidemiology.