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Research

• 8

  Apr
  Using the zoophytophagous plant bug, Nesidiocoris tenuis, for the control of Tuta absoluta in tomato: Its direct effects on the plants and their yield and its control efficacy

  Plant Protection

  by Danit Parker

  אורגני; הגה"צ; ירקות

  תאריך עדכון 14/3/2012

  Using the zoophytophagous plant bug, Nesidiocoris tenuis, for the control of Tuta absoluta in tomato: Its direct effects on the plants and their yield and its control efficacy
  Danit Parker, Ela Yosel, Shimon Pivonia, Rachel Levite – Central and Northern Arava Research and Development
  Arnon Allush and Shimon Shtainberg – Bio-Bee.
  E-mail address for correspondence: shimonp@arava.co.il

  Abstract
  Tuta absoluta is a new pest in Israel that causes a great deal of damage to different crops, especially tomato. In the U.S., T. absoluta is considered a quarantine pest. This species is a member of the Order Lepidoptera and the Family Gelechiidae. After the larvae of this species emerge, they burrow through leaves to fruit and stems, forming characteristic tunnels and trenches. Sometimes the larvae will penetrate the stems and tips of the canopy, strangling these tips and causing them to wither. The adult of the species is about 10 mm long. The control measures and materials available for use against this insect are not sufficient, especially those that can be used in organic agricultural systems, for which the number of permitted products is extremely limited. In response to the recent spread of this species throughout the Mediterranean basin, intensive studies have been conducted in many areas with the goal of developing ways to cope with this problem. One area of this research is the development of an integrated management system involving the local natural predator Nesidiocris tenius, which is particularly suited to tomato. N. tenius is a member of the Order Hemiptera and the Family Miridae. The adults of this omnivorous species can feed on animals or plants. N. tenius feeds on eggs and first-stage larvae of the T. absoluta moth and, therefore, holds potential for use as a biological control agent against this species. When this insect subsists on a plant diet, it sucks the sap from leaves, stems and young fruit, creating bands of dead tissue that can lead to the desiccation and eventual shedding of leaves and fruit.
  In an experiment conducted at the Yair Experimental Station during the 2010/11 season, we examined the efficacy of N. tenuis against the moth T. absoluta, evaluated the level and character of the damage N. tenuis caused to tomatoes in the greenhouse and compared the biological-control efficacy of this insect with the amount of damage it caused to the tomato crop. The experiment was conducted using tomato line 1402 (Hazera). At the beginning of the season, T. absoluta was not present in the tunnels we were using for the experiment and we focused on evaluating the level of direct damage caused to the tomato plants by N. tenius. We evaluated three treatments with different levels of N. tenius: unregulated, regulated and a N. tenius -free control. When T. absoluta appeared in the tunnels, we examined the effects of the treatments listed above on the level of damage T. absoluta was able to inflict on the tomato plants and their yield.
  The regulated N. tenius treatment included chemical intervention each time there were more than five individuals per stem meristem. It was very difficult to control the N. tenius population using the chemicals labeled for use in organic agriculture. We found that the N. tenius caused a lot of leaf damage, but did not negatively affect yield over the winter or through April. Later on, there could have been a certain amount of damage related to the dramatic increase in the N. tenius populations. Next season, we will also examine the effect of N. tenius on the quality of cluster tomatoes in addition to its effects on tomatoes that produce individual fruits (as we examined this year). It is possible that the damage to the main stem caused by N. tenius will negatively affect the crop. After T. absoluta appeared in the tunnels in March, we found less T. absoluta-inflicted damage in the leaves and fruit in the N. tenius treatments than in the control. The lowest level of T. absoluta damage was observed in the regulated N. tenius treatment. This is apparently due to the fact that the product that was used to control N. tenius in this treatment (Tracer; spinosad) also controls T. absoluta. Experiments with N. tenius and the evaluation of its efficacy against T. absoluta in organic crops will continue in the coming season.

  שפה English
  מחבר Danit Parker, Ela Yosel, Shimon Pivonia, Rachel Levite, Arnon Allush, Shimon Shtainberg
  שנה 2011
  שייכות yzvieli
  תאריך יצירה 14/3/2012
  תאריך עדכון 14/3/2012
• 8

  Apr
  Control of Pythium in pepper during the summer in the Arava

  Plant Protection, Vegetables

  by Shimon Pivonia, Ph.D.

  הגה"צ; ירקות

  תאריך עדכון 14/3/2012

  Control of Pythium in pepper during the summer in the Arava
  Shimon Pivonia, Rachel Levite – Central and Northern Arava R&D
  E-mail address for correspondence: ShimonP@arava.co.il

  Abstract
  Pepper crops in the Arava are attacked by a number of different Pythium species. Early in the season, the plant can be negatively affected by Pythium species that develop best at particularly high temperatures, particularly Pythium aphanidermatum. Pythium can kill plants at the germination stage. Later, when conditions are mild, like those found in a nursery, the plants are not sensitive to Pythium. When young plants are transplanted into a field they are exposed to the temperatures prevailing in the Arava during August, which makes them once again sensitive to Pythium infection. Plants that have been infected by Pythium lose their turgor during the day and recover in the evening and this can continue until temperatures drop. Some of the infected plants are not able to recover and die. The yields of Pythium-infected plants are expected to be significantly less than those of healthy plants.
  The goal of this work is the evaluation of appropriate materials for the control of Pythium in the field during the summer. Within the framework of this work, which was conducted at the Yair Experimental Station during the 2010/11 season, a method was developed for simulating the death of plants in the field in a controlled growth chamber. This allowed the evaluation of a wide range of treatments. None of the biological treatments and plant-resistance treatments that were evaluated provided effective control of Pythium damage in pepper. Of the fungicides evaluated in the growth chamber, Ridomil (metalaxyl + mancozeb) and Tachigaren (hymexazol) were the most effective and these materials were also evaluated under field conditions. In the field, the most effective treatment was a combination of Tachigaren applied in the nursery about two days before the plants were transplanted into the field with an application of Ridomil in the field about 5 days after transplanting. Fields that have been disinfected are generally free of summer pythium disease and the young plants generally arrive from the nursery free of the pathogen. Therefore, it appears that in the future, when legal permission is given for the practice, an application of Tachigaren to the young plants before they are transplanted may be sufficient. In plots in which signs of plant collapse following infection with Pythium are observed, one or more applications of Ridomil may be made depending on the level of infection.

  שפה English
  מלות מפתח Capsicum, metalaxyl, hymexazol
  מחבר Shimon Pivonia, Rachel Levite
  שנה 2011
  שייכות yzvieli
  תאריך יצירה 14/3/2012
  תאריך עדכון 14/3/2012
• 8

  Apr
  The effects of soil disinfection and the insertion of crop residue into the soil on pepper yields – A long-term analysis

  Plant Protection, Vegetables

  by Shimon Pivonia, Ph.D.

  הגה"צ; ירקות

  תאריך עדכון 14/3/2012

  תיאור מלא The effects of soil disinfection and the insertion of crop residue into the soil on pepper yields - A long-term analysis
  Shimon Pivonia, Rachel Levite, Ami Maduel – Central and Northern Arava R&D
  E-mail address for correspondence: shimonp@arava.co.il

  Abstract
  Pepper is the main crop in the central Arava and 17,500 dunams (1,750 Ha) in this region were planted to pepper during the 2010/11 growing season. Previously, it was customary to disinfect the soil with methyl bromide before the start of the season. With the end of the use of methyl bromide about five years ago, growers began using metham sodium preparations to disinfect their soil. Since then, in most areas, no particular problems involving soilborne diseases have been observed, aside from a certain increase in the number of plants collapsing as a result of Pythium infection in the winter and the appearance of the new phenomenon of damage to plants caused by the free nematode Pratylenchus penetrans.
  We are conducting a long-term evaluation of the effects of soil-disinfection treatments on pepper development and yield. This study is being conducted on the same ground each year (fixed plots). The study has been conducted for four growing seasons (2007/8, 2008/9, 2009/10 and 2010/11) and we plan to continue this work for two more seasons. During the last two years, we also evaluated the effects of inserting crop residue into the soil (in the same fixed plots). Today, there is a need for alternative solutions for removing and destroying crop residue at the end of the season. The alternative of burying the residue in the field is favored for the significant labor savings it provides as well as for other reasons, as long as it does not negatively affect the next season’s crop.
  This study was set up at the Zohar Experimental Station in Sodom Valley in a greenhouse in which pepper had been grown in the past. We do not know of any particular problems with soilborne pests in this spot before the start of our experiment. The first three years of the study, the pepper cv. Celica was used and, in the year upon which we are currently reporting (2010/11), line 7158 was used. At the end of the first two seasons of the study, we did not see any notable difference between the pepper yield of the control treatment and the yields of the soil disinfection treatments, which included solarization, solarization + Edigan (metham sodium), and Edigan applied through the drip-irrigation system in the absence of any solarization. Despite the fact that no notable yield loss was observed in the untreated control plot, the plants in the untreated control plot did not look as nice. At the end of the third year, the yield of the untreated control was noticeably less than the yields of the other three treatments. In the fourth year, the area that had been used for the untreated control treatment during the previous three years was subjected to a solarization treatment. At the end of the season, we did not notice any yield loss for this treatment. At the end of the second year of the evaluation of the effect of burying crop residue, we did not note any difference between the treatments in which residue from the previous crop was inserted into the soil, green or after having been burnt down with Edigan, and the treatments in which the crop residue was removed from the field.

  Acknowledgement
  We thank the Plant Board for their financial support of this research.

  שפה English
  מלות מפתח Capsicum, soilborne diseases
  מחבר Shimon Pivonia, Rachel Levite, Ami Maduel
  שנה 2011
  שייכות yzvieli
  תאריך יצירה 14/3/2012
  תאריך עדכון 14/3/2012

  OPEN
• 25

  Mar
  Development of a system and machinery for collection and removal of crop residue from protected plots

  Orchard, Vegetables

  by Yossi Kashti

  11
  תחום או ענף אגרוטכנולוגיה; אורגני; ירקות

  תאריך עדכון 14/3/2012
  Development of a system and machinery for collection and removal of crop residue from protected plots
  Y. Kashti, I. Sagi, O. Kesar, A. Levi, F. Geoola, R. Brikman – Institute of Agricultural Engineering, ARO
  A. Gadiel – Central and Northern Arava R&D
  R. Amir – Extension Service, Ministry of Agriculture and Rural Development
  E-mail address for correspondence: ykashti@volcani.agri.gov.il

  Abstract
  At the end of a season of vegetable production in a greenhouse, the plants are manually removed. This process requires 3 work days and 5 tractor hours per dunam. The material is removed for sanitary reasons, to avoid the transmission of diseases to future crops. The amount of greenhouse vegetable production in Israel stands at 65,000 dunams. Thousands of work-days are spent removing the remains of old crops from these areas.
  The goal of this research is the development of a method and equipment for the mechanization of this process. Examination of the matter led to the identification of three possible methods for mechanized removal of crop residue. We chose to more closely examine the cheapest of these methods. The chosen method includes three mechanized activities that are carried out one after the other with the help of the farm tractor. The activities are: uprooting the plants, concentration of the uprooted plant material in a bin and collecting and chopping up the plants as they are collected as preparation for the production of compost. Over the last two years, we examined the process of removing crop residue from greenhouses with the help of different types of existing equipment, machines that were specially prepared and tested and machines that were purchased from different manufacturers. We tested the abilities of four types of uprooting machinery to uproot whole plants and crop residue: a knife uprooter with one central leg, a knife uprooter with two side legs, a disc uprooter and a finger uprooter. A piece of equipment based on a set of pitchforks was evaluated in an area thick with whole plants and residue. We evaluated the efficacy of two types of mowers for collecting and chopping up whole plants.
  The mechanized residue removal experiments were conducted in the western Negev and the central Arava. The experiments were conducted in pepper plots in screen-houses and greenhouses belonging to different developers, on sandy and sandy/loess soils, with varying agro-technical specifications (plot width, number of rows per plot, distance between rows, etc.) The main experiments were conducted in the Arava beginning in early May, immediately after the last harvest while the plants were still green and continued each month until the plants withered.
  After two years of research, the results of this work show that the optimal timing for removing crop residue is immediately after the last harvest while the plants are still green. At that point, few leaves and fruit are cut-off from the plants and dropped to the ground. We also found that collecting plant matter and then depositing it in place with a mower that includes a container and has no pick-up (wheel with lifting fingers) left the area cleaner. The finger plow successfully uprooted crop remains in moist and dry soil.
  Based on the results obtained from two seasons of research (2009/10 and 2010/11), it appears that the possible process for mechanized removal of crop residue includes two phases: 1) mowing with a mower that includes a container immediately after the last harvest, while the plants are still standing in the ground; and 2) uprooting and collecting the crop residue. Therefore, before the third year of this research, we will build a mower without pick-up that has a large container that will be sufficient for the collection of plants from at least two plots and the collection of the crop residue after uprooting.

  Acknowledgements
  We thank the growers, Noa and Atar Sahak from Hetzva and the staff and management of the Besor Farm and the Yair Farm, on whose property experiments were carried out, for their help. We thank Amotz from the Ego Company and Aharon Yemini for contributing the piece of equipment based on a set of pitchforks and the mower for the first experiments. We thank Motti Ben-Ami from the Ein Yahav welding shop for helping us with tool repair. Special thanks to Ram Golan, on whose farm the main experiments were carried out, for dedicating his time and effort to this project and for very pleasantly providing us with advice and technical equipment. Thank you to Mickey Kaplan, Central and Northern Arava R&D Tamar, as well as the office of the Chief Scientist of the Ministry of Agriculture for financial support for research project no. 458-0518-09.

  שפה English
  מלות מפתח vegetable, greenhouses, pepper, capsicum
  מחבר Yossi Kashti, I. Sagi, O. Kesar, A. Levi, F. Geoola, R. Brikman, A. Gadiel, R. Amir
  שנה 2011
  שייכות yzvieli
  תאריך יצירה 14/3/2012
  תאריך עדכון 14/3/2012