Diversity of Botryosphaeriaceae causing grapevine trunk diseases and their spatial distribution under different climatic conditions in Algeria

The family Botryosphaeriaceae is one of the most widespread and cosmopolitan endophytic group of fungi. Every year, species of this family cause severe damages on table and wine grape production, worldwide. However, this threat is still poorly known in Algeria. In this study, a large number of Botryosphaeriaceae-like isolates were obtained from symptomatic grapevines collected from eight regions with different ecological conditions, namely: Boumerdès, Médéa, Algiers, Tipaza, El Taref, Sidi Bel Abbes, Biskra and Adrar. The isolates were identified using DNA sequences of the translation elongation factor (tef1-α) and internal transcribed spacer (ITS) regions. Eleven species belonging to six genera, including Neofusicoccum parvum, N. algeriense, N. vitifusiforme, N. stellenboschiana, N. luteum, Diplodia seriata, D. olivarum, Lasiodiplodia theobromae, Dothiorella sarmentorum, Botryosphaeria dothidea and Neoscytalidium dimidiatum were identified. The spatial distribution of the Botryosphaeriaceae showed that D. seriata and N. stellenboschiana were the most widespread in the Algerian vineyards, while L. theobromae was recorded in the desert region of Biskra. Pathogenicity trials showed that all species were pathogenic on detached green shoots of grapevine, with N. parvum and L. theobromae being the most aggressive.

     

Vegetative,Chemical Status and Productivity of Zucchini Squash (<Emphasis Type="Italic">Cucurbita pepo</Emphasis> L.) Plants in Responses to Foliar Application of Pentakeep and Strigolactones Under NPK Rates

In order to determine the effect of two bio-stimulants under NPK fertilizer rates on growth and nutrient content and yield of zucchini (squash), an experiment was conducted at Mendel university during 2014. The treatments included four NPK rates namely, 0, 75, 100 and 150% of recommended rate in combination with foliar application of Pentakeep super and strigolactones (alone and in combination) were used. This study was arranged in a split plot design in three replications. The results showed NPK at 150% led to the maximum significant increase of growth characters i.?e., leaf number, fresh and dry weight of leaves relative to unfertilized control. Chlorophyll reading increased significantly with increase in NPK supply up to NPK75%. The highest contents of N, K and nitrate were found in zucchini leaves treated with NPK at 150% of recommended rate. Yield and its component increased significantly with increase in NPK supply up to 100% of recommended rate. The combined application of Pentakeep super and strigolactones significantly maximized growth characters and fruit yield as compared to control treatment. The highest content of N generated in plants sprayed with Pentakeep super while application of Pentakeep and strigolactones did not affect the P and K contents. Whereas, control plants effectively significantly increased the chlorophyll and nitrate content of leaves.