With at least 1.3 million described species of insect, accounting for at least two-thirds of known organisms, it’s no wonder that entomology fascinates the human race. And yet understanding and studying insects is not just for those with an interest in the creatures; information and knowledge on insects affects farmers and agricultural producers who may wish to be able to control the populations living and feeding on their crops. With such huge numbers of species, it’s easy to imagine the potential damage to crops, and why over the centuries humans have become fascinated with the control of these creatures, particularly in an agricultural setting.
Crop pests can take on different forms through their lifecycle, from larvae through to the final adult stage, and can cause havoc for farmers both above and below ground. The damage caused by insects living above the ground is often more easily identified and treated than the insects living below ground on the roots of plants, so crop losses from soil insects are often underestimated, and sometimes even not recognised as being caused by insects. White grubs, the larvae of chafer beetles, are one group of species for which this is true, with below-ground damage to plants often being extensive and in some cases causing the death of the plants. This complexity is further compounded by the fact that some soil pests feed on different plants at the different stages of their lifecycle, both above and below the ground. Scientists in India noted devastating effects on teak (Tectona grandis) seedlings in the nursery beds at the Ramdongari Forest Nursery in central India associated with the presence of white grubs, with the plant destruction causing severe economic effects. Little is often known about the biology and ecology of such white grubs, making them one of the toughest pests to manage, often leading to the high use of chemical insecticides, rather than Integrated Pest Management (IPM) schemes.
Teak is an important part of India’s economy by virtue of its timber quality, popularity and ever-increasing demand; it is highly prized by ship builders and manufacturers of outdoor furniture (amongst others) due to its ability to withstand most weather conditions. Combine this with the difficulty of managing white grubs, and it’s no surprise that Dr Nitin Kulkarni from the Tropical Forest Research Institute in Jabalpur, India chose to investigate the effect of the larvae of the chafer beetles Holotrichia rustica and H. mucida on teak seedlings. The area studied (Ramdongari Forest Nursery) accounts for around 500,000 to 800,000 teak seedlings per year and supplies seedlings for state forest departments and non-governmental organisations, including small farmers, across central India, so is of significant economic importance to the region.
The researchers observed and recorded data on the adult beetle emergence, their host preferences and populations, as well as the grub populations and damage to the teak seedlings. They found that typically the seedlings wilt due to the roots having been eaten, and often die. The insect count and plant damage data collected over the four years of the study were analysed in GenStat Discovery Edition 3, the free version of GenStat available to the developing world, using analysis of variance followed by the multiple comparison of means. Dr Kulkarni said “GenStat covers most of the statistical analyses and yet, is very user friendly with appropriate demonstrations.”
It was noted that the adult beetles emerged from the teak beds and became active at the onset of the monsoon season, when humidity had risen rapidly after pre-monsoon showers, and remained active for approximately 18 days. Importantly, they observed that whilst the adult beetles fed and mated on the leaves of jujube and other Ziziphus species, immature grubs of both species fed on the fine rootlets and main roots of teak seedlings. It has therefore led to the suggestion that it may be possible to control this pest with an IPM approach by targeting adults rather than applying chemicals against the larvae. With adult activity triggered by measurable weather conditions – falling temperatures and increased humidity – manual collection of the adults on the shrubs growing on nursery field edges appears one viable option for managing the pests without use of toxic chemicals, as part of an IPM program.
Information and results from research such as this has wider reaching impacts for entomologists looking at other white grub species, many of which are pests of food crops across the developing world. As well, the research progresses research into effective pest-management techniques, in this case on the chafer beetles in Indian teak nurseries.
Imagine needing to conduct research of this nature but with limited access to the appropriate tools, specifically appropriate data analysis software. Unfortunately researchers and scientists in the developing world don’t always have access to the tools they need for their work; however data analysis software is something they do have access to. With GenStat Discovery edition 3 these researchers were able to use high quality, respected and appropriate software to conduct their analysis, and so provide farmers – and in this case, teak nurseries – with relevant advice and assistance on the cultivation and protection of their crops.
GenStat Discovery edition 3, is widely used across the developing world to assist in analysing and visualising data. It is free to non commercial establishments across the developing world. For more details or to download look at the VSNi website.
Our thanks to Dr Rogers of Research Connections and Consulting and to Dr Kulkarni of the Tropical Forest Research Institute. Dr Rogers provides pesticide-efficacy data analysis services to the crop-protection industry and also assists authors with the preparation and submission of scientific publications.
The original paper (abstract) is available from Wiley Interscience
The GenStat Discovery licence is valid for one calendar year, but a new licence key will be automatically sent to you in December, irrespective of when you originally downloaded it if you register, meaning you never need be without it, nor do you need to download another version, at the end of the year.
Users who have obtained their copy of GenStat Discovery through an old or a colleague’s CD, may find they need to request a new licence key from support, if the GenStat Discovery CD was made prior to the current year.
To register your copy of GenStat Discovery visit the registration webpages.
VSNi run training courses throughout the year on a variety of topics, and we are always updating the schedule. Our next courses on GenStat are scheduled for April 2010.
Introduction to GenStat will take place on Monday 19th April 2010 at Apsley Paper Trail in Apsley, Hertfordshire, UK. This course is aimed for those who need an overview of GenStat and the sklls to start them analysing and visualising data.
For users who are confident with the menu system and wish to develop their skills in programming in GenStat, the Introduction to the GenStat Command Language is being held on Tuesday 20th April 2010, again at the Apsley Paper Trail.
We’re pleased to tell you of additional courses in statistics run by colleagues at the Statistical Services Centre at the University of Reading; all of which allow time for practicals for the attendee to put into practise what they have learnt:
E-SMS – a popular online course about understanding variability (next run scheduled 22nd March-10 May). It includes the essentials needed to describe data well (descriptive statistics) and to make good generalisations (statistical inference). It also covers the concept and uses of p-values, and establishes the groundwork for statistical modelling based on simple linear regression. Find out more at e-SMS website.
Review of Basic Statistics (19-20 April) – this course covers the basic ideas of statistcs needed in research systematically and quickly. Mathematical details are kept to a minimum, but concepts such as hypothesis tests, t tests, different distributions are all covered.
Regression Analysis: A Hands-on Approach (21-22 July) – Regression is a powerful technique for studying relationships between quantitative variables. Summarising relationships by the most appropriate equation (modelling) is very quick using Genstat. Find out more about the details on this course.
Introduction to ANOVA – (21-22 April) is a key technique popularly used in analysing research data. Every serious researcher needs to acquire skills in using this technique, and to have a good appreciation of the underlying concepts.
What Sample Size do I need? (1 December) Choosing an appropriate sample size is a common problem and should be given due consideration in any research proposal, as an inadequate sample size invariably leads to wasted resources. This course aims to give a practical introduction to sample size determination in the context of some commonly used significance tests.
More details on these courses and the Statistical Services Centre is available at the SSC website.
From 11-16 July 2010, VSNi’s CEO, Stewart Andrews will be presenting GenStat for Teaching at ICOTS8 in Slovenia. ICOTS8 in Ljubljana in Slovenia.
If you would like to meet with Stewart at one of this event please email Stewart Andrews to arrange the details.
We’re always updating the list of events we can support and sponsor – so please send us details of any events you are organising or involved in, and as we decide on more events for the future we’ll list them on our website.