SATrends Issue 67 June 2006
  • Neem: the bitter truth
  • Jaguars, giraffes and g’nuts!
  • Fighting felons with firewalls
  • The power of predictions and probabilities

  • 1. Neem: the bitter truth
    top

    The insecticidal properties of plants have been known through the ages. In recent years botanical insecticides have played a critical role in the management of several insect pests. However, they have not been fully exploited on a commercial scale. Neem (Azadirachta indica) has been the focus of studies for over 20 years, and neem products are used as pesticides and allied chemicals against >250 insect species all over the world.

    Neem fruit, flowers and foliage.

    Results from several global pest management programs using neem have been spectacular. Neem products were believed to be harmless to natural enemies of the pests, pollinators and other non-target organisms, so Integrated Pest Management (IPM) programs adopted neem as one of the prime options for greater stability and sustainability in crop production. Yet, although there is much discussion about the advantages of neem, information about its toxic effects on beneficial organisms is not thoroughly understood.

    ICRISAT studies on the efficacy of different IPM components (neem 1500 ppm, 1750 ml / ha, endosulfan 0.07% and NPV 250 LE / ha) on chickpea pod borer management revealed neem application ill effects on soil inhabiting and aerial natural enemies. Soil inhabiting natural enemies - ants, carabid beetles, spiders, crickets and earwigs -- was collected from the pitfall traps fixed in each treatment of the experiment. Aerial natural enemies such as braconids, ichneumonids, and ants of the order Hymenoptera, apart from these spiders and tachinids were also observed. Sampling was done with a De Vac (suction trap) to assess the effect of IPM components on aerial natural enemies.

    The overall effect of neem was evident on soil dwelling natural enemies. Endosulfan was instrumental in reducing upto 63% natural enemy population compared to 38% in plots treated with neem and 31% in IPM plots which had received neem, HNPV and endosulfan at different stages of the crop.

    The observations on aerial sampling of natural enemies with De Vac suggested a significant reduction of enemy populations in plots treated with endosulfan, neem and IPM with 56%, 28%, and 48% respectively at different stages of the crop.

    Evidently, neem products are not as safe to the natural enemies as they were once believed. The results indicated that when neem was applied to control chickpea pests there was an overall 38% reduction in soil inhabiting and 28% reduction in aerial natural enemy populations. Therefore, considering the neem effects on natural enemies, we need to judiciously select management measures that help to maintain an ecological balance and healthy environment.

    For more information contact g.rangarao@cgiar.org

    2. Jaguars, giraffes and g’nuts!
    top

    Jaguars and giraffes have spots from birth, which are part of their distinctiveness. On the other hand, if spots are discovered on a groundnut plant midway in its life cycle, the plant is sure to lose its distinctiveness as more likely than not it has fallen prey to fungal pathogens. Two fungal diseases, the early leaf spot and late leaf spot disease, cause brown to black spotting on the leaves of the plant, damage the crop, and bring down the yield.

    ICG 4983, a wild relative of groundnut.

    Early leaf spot is caused by the fungus Cercospora arachidicola, one of most dreaded foliar pathogens, which causes severe damage to groundnut in several parts of the world. Reports indicate that yield losses due to this pathogen alone vary from 10 to 50% depending on the agro-ecological zone where it is grown and the genotypes cultivated. Late leaf spot is caused by Phaeoisariopsis personata, the damage of which can cause economic losses in both Asia and Africa.

    ICRISAT is actively involved in developing foliar disease resistant groundnuts. Fortunately, many of the wild relatives of groundnut are good sources of resistance to both early and late leaf spot diseases. These wild relatives have been used in the wide crosses program and sources of resistance obtained from them have been successfully transferred. This has been possible through active collaboration between groundnut pathologists. The foliar disease resistant lines that have been developed with genes from wild Arachis are ICGV 86699, ICGV 87165, ICGV-SM 86715 to name a few.

    For an ever-changing scene of disease dynamics, and a sustainable groundnut improvement program, new sources of resistance need to be constantly identified, and that exactly is what happens at ICRISAT. Groundnut pathologists continue to identify new sources of resistance to leaf spots in wild Arachis, so that the wide crosses program can use these sources in their pre-breeding program. Recently, sources of resistance to late leaf spot were identified in the progenies resulting from crosses of A. stenosperma, A. kempff-mercadoi, A. diogoi and A. cardenasii, thus promising breeds of groundnuts free from spots and blemishes.

    For more information contact n.mallikarjuna@cgiar.org

    3. Fighting felons with firewalls
    top

    The world has witnessed a proliferation of Information and Communication Technology in the last two decades. Academics, business and industry, military, press and media - everyone has embraced the technology and benefited.

    While the quest for innovation was at its peak, somewhere in the darker corners of the globe a breed of hackers and malicious code developers were busy applying their intellectual capabilities to no good, probably driven by curiosity, rebellion, hate, discontent, and more. The world then came up against the negative side of development. Initially the damage was confined to business and military circles, but eventually hackers turned their sights on academic and research communities too.

    Today's complex and evolving threats can steal valuable data, disrupt networks, and cause vital resources to be unavailable to users. Organizations need comprehensive, integrated solutions for effective protection and risk mitigation.

    Hacking means illegally accessing other people's computer systems to destroy, disrupt or carry out illegal activities on the network or computer systems, or on the Computer Environment.

    A Computer Virus is a dangerous computer program that can generate copies of itself, thereby spreading itself. Most computer viruses have a destructive payload that is activated under certain conditions.

    Academic and research communities are not spared by hackers and do not escape unhurt from computer virus attacks. Precious data has been lost or stolen, and important documents been made unavailable. Precious research bound resources need to be diverted to create a secure infrastructure.

    The war against hacking is fought with a firewall. A firewall is a dedicated machine with special security features, and is typically used to protect an internal network connected to an outside network, especially the Internet. ICRISAT has built a state-of-the-art multi-layer firewall using a router and dedicated firewall server. Access to ICRISAT soft resources from the Internet is further protected by routing it through another firewall/switching server.

    Computer viruses are fought with anti-virus software. These are programs that run in the background and scan the computer's memory and all files and diskettes that are accessed, for known and unknown viruses, before removing them. ICRISAT has installed anti-virus software to protect computers. This is complemented by anti-virus solutions implemented by CGNET Services International, who check in-bound and out-bound e-mail for viruses.

    During the last year, the ICRISAT firewall server has logged more than 1500 unsuccessful hacking attempts on its soft resources. Happily, ICRISAT has not experienced any major infringement on its computers.

    For more information contact p.modi@cgiar.org

    4. The power of predictions and probabilities
    top

    Monsoon rainfall in India varies every year, and distribution is uncertain. This poses a production risk for farmers in the semi-arid India.

    Farmers tend to ignore rainfall forecasts issued by the Indian Meteorological Department (IMD) while making crop decisions since they are made for the whole country, and could be unreliable regionally. Recent advances in forecasting techniques improve the usefulness of forecasting seasonal rainfall. Farmers in USA, Australia, Argentina and Brazil benefit from forecast-based cropping decision options to enhance agricultural productivity. ICRISAT, in collaboration with Acharya NG Ranga Agricultural University, worked on a pilot project funded by International START, USA, and provided seasonal rainfall forecast-based discussions aided by crop models to guide farmers' decision-making in the Kurnool and Anantapur districts in southern India.

    Farmers discuss cropping decisions.

    Rainfall data (since 1937 for Nandyala in Kurnool, and since 1962 for Anantapur) was analyzed to assess the variability in length of crop growing season, and to estimate cropping systems productivity. We assessed statistical forecasting techniques and the El Niño/Southern Oscillation phase analyses to identify forecast signals. A model output statistical downscaling technique was employed on General Circulation Model precipitation fields provided by IRI, New York, to predict seasonal rainfall for Anantapur and Kurnool. Predicted rainfall totals were disaggregated to daily rainfall (useful for crop model APSIM) to simulate crop yield scenarios for different decision options.

    Probabilistic seasonal precipitation forecast was communicated to farmers at one-month lead-time. The value of forecast was assessed in the hindcast analysis using crop-modeling by (i) estimating crop yields with traditional practices of risk-averse farmers, (ii) crop production estimates from adoptive farmers' forecast based decisions. Twenty-one adoptive farmers, from a group of fifty selected farmers in two districts, assessed rainfall forecast based cropping decisions on their fields. In Anantapur, farmers had mixed experiences following forecast based decisions of the peanut/short duration pigeonpea intercrop system resulting in an average yield advantage of 300 kg ha-1 peanut, and a decision of peanut/medium duration pigeonpea resulted in an average yield loss of above 300 kg ha-1 peanut, compared to the risk-averse decision of sole peanut system, when our forecast failed. In Kurnool, rainfall forecast decisions of farmers on double cropping options of intercrops and sequential crops provided economic returns in the range of Rs 9329 ha-1 to Rs 22, 278 ha-1($216 to $518).

    In the March 2004 evaluation meeting, farmers expressed interest to assess rainfall forecasts for 3 seasons by implementing cropping decisions, to up-scale forecast applications further. Clearly, farmers now have a new awareness about forecast-based decisions.

    For more information contact v.nageswararao@cgiar.org