Population dynamics of major phototactic insect pests of chickpea ecosystem through light trap

2019 ◽  
Author(s):  
Amit Kumar Sharma ◽  
Rajesh Aarwe ◽  
A. K. Bhowmick ◽  
A. S. Thakur ◽  
Radheshyam Sharma
Keyword(s):  
Population Dynamics ◽  
Relative Humidity ◽  
Wind Velocity ◽  
Helicoverpa Armigera ◽  
Insect Pests ◽  
Light Trap ◽  
Activity Period ◽  
Maximum Temperature ◽  
Agrotis Ipsilon ◽  
Helicoverpa Armígera

An investigation was carried out at Experimental Farm, JNKVV, Jabalpur (MP) during 2016 - 2017 to know the population dynamics of major phototactic insect pests using Jawahar light trap in chickpea ecosystem. The present study revealed that gram pod borer was first recorded during 45th SW in light trap. The activity period of Helicoverpa armigera was noticed from November 2016 to April 2017 with two distinct peaks during 13th and 14th SW. The highest peak was observed in 14thSW. Cutworm was first recorded during 46th SW in light trap. Three distinct peaks were observed during 4th, 12th and 16th SW with highest peak was observed in 12th SW. Tobacco caterpillar was also firstly recorded during 46th SW in light trap with one distinct peak during 13th SW. Further, the correlation studies revealed that maximum temperature, minimum temperature, sunshine, wind velocity, morning vapor pressure and evaporation showed significant positive correlation whilemorning relative humidity and evening relative humidity, showed negative correlation with Helicoverpa armigera, Agrotis ipsilon (Hufnagel) and Spodoptera litura (Fabricius) moth catches and statistically found significant except wind velocity which wasnon-significant against Agrotis ipsilon (Hufnagel). Rest of the weather parameters were found non-significant.

scholarly journals Influence of prevailing weather parameters on population dynamics of fruit borer, Helicoverpa armigera (Hübner) on tomato in Haryana

2021 ◽  
Vol 21 (2) ◽  
pp. 193-196
Author(s):  
SHIVANI KHOKHAR ◽  
KRISHNA ROLANIA ◽  
GAURAV SINGH ◽  
ANIL KUMAR
Keyword(s):  
Relative Humidity ◽  
Helicoverpa Armigera ◽  
Significant Positive Correlation ◽  
Linear Regression Analysis ◽  
Maximum Temperature ◽  
Population Fluctuations ◽  
Larval Population ◽  
Positive Correlation ◽  
Helicoverpa Armígera ◽  
Weather Parameters

A field experiment was conducted for two years (2016-17 and 2017-18) at Entomological Research Area, Department of Entomology, CCS Haryana Agricultural University, Hisar to ascertain the influence of various meteorological parameters on population fluctuations of Helicoverpa armigera on tomato. The maximum oviposition (4.60 eggs/ plant) was recorded during 15th standard meteorologicalweek (SMW) whereas larval population was at peak (4.91 larvae/ plant) during 16th SMW. The larval population showed significant positive correlation with maximum temperature (r=0.617*) and highly significant negative correlation with morning (r=-0.784**) as well as evening relative humidity (r=-0.814**). Maximum eggs parasitization (12.85 %) by Trichogramma sp. was recorded during 16th SMW. These trichogrammatid parasitoids exhibited non-significant correlation with weather parameters and highly significant positive correlation (r=0.976**) with egg counts of H. armigera. Multiple linear regression analysis showed that 77 per cent (R2=0.77) variability in larval population was accounted by weather parameters particularly maximum temperature, morning and evening relative humidity. 

scholarly journals PENGARUH KOMPOSISI MEDIA TERHADAP PERTUMBUHAN JAMUR Nomuraea rileyi (FARLOW) SAMSON DAN PATOGENISITASNYA PADA Helicoverpa armigera HUBNER DAN Spodoptera litura F.

2020 ◽  
Vol 17 (3) ◽  
pp. 102
Author(s):  
NURUL HIDAYAH ◽  
I.G.A.A. INDRAYANI
Keyword(s):  
Growth Rate ◽  
Yeast Extract ◽  
Entomopathogenic Fungi ◽  
Helicoverpa Armigera ◽  
Spodoptera Litura ◽  
Insect Pests ◽  
Medium Composition ◽  
Nomuraea Rileyi ◽  
Conidia Production ◽  
Helicoverpa Armígera

<p>ABSTRAK</p><p>Nomuraea rileyi adalah salah satu jamur entomopatogen yangpotensial mengendalikan hama Helicoverpa armigera dan Spodopteralitura pada tanaman kapas, tembakau, dan jarak kepyar. Di lapanganpernah ditemukan larva hama H. armigera dan S. litura yang terinfeksisecara alami oleh N. rileyi yang mengindikasikan bahwa N. rileyiberpotensi sebagai agens hayati. Sebelum N. rileyi dikembangkan sebagaiagens hayati, maka perlu diketahui metode perbanyakannya pada mediabuatan. Penelitian bertujuan untuk mengetahui komposisi media tumbuhyang sesuai untuk perbanyakan N. rileyi dan pengujian patogenisitasnyaterhadap H. armigera dan S. litura. Penelitian dilakukan di LaboratoriumFitopatologi dan Laboratorium Patogen Serangga Balai PenelitianTanaman Tembakau dan Serat Malang mulai bulan Mei sampai denganNovember 2009. Penelitian ini terdiri atas 2 pengujian, yaitu pengujiankarakter biologi N. rileyi dan patogenisitas pada ulat H. armigera dan S.litura. Dalam pengujian karakter biologi jamur diuji 4 macam mediaperbanyakan, yaitu: (1) Sabouraud maltose agar + ekstrak yeast (SMAY),(2) Sabouraud maltose agar + ekstrak yeast + ekstrak beras (SMAYB), (3)Sabouraud maltose agar + ekstrak yeast + ekstrak kentang (SMAYK), dan(4) Media lengkap untuk N. rileyi (MLNr), serta 2 tingkat suhu inkubasi,yaitu 23±1 dan 27±1ºC. Perlakuan disusun dalam rancangan acak lengkap(RAL) dengan lima kali ulangan. Setiap media disiapkan di dalam 10cawan petri per perlakuan dan masing-masing diinokulasi dengan 10 5konidia/ml. Parameter yang diamati adalah laju pertumbuhan jamur danproduksi konidia. Sedangkan dalam pengujian patogenisitas konidia N.rileyi terhadap larva H. armigera dan S. litura dilakukan dengan metodepelumuran (painting), yaitu ulat diletakkan di atas konidia di dalam cawanpetri selama ± 10 detik kemudian dipindahkan ke vial-vial plastikberdiameter 2,5 cm berisi pakan daun kapas muda (± 1 cm 2 ) untuk H.armigera dan daun jarak kepyar untuk S. litura. Apabila pakan daun telahhabis, serangga diberi pakan buatan berbahan dasar tepung kedelai. Pakanbuatan diganti setiap 2 hari sampai ulat menjadi pupa. Selanjutnya ulatyang telah diperlakukan dengan jamur diinkubasi-kan pada suhu ruang(27°-29°C) selama ± 14 hari dan diamati perkembangan ulat maupunjamurnya setiap hari. Parameter yang diamati adalah mortalitas ulat H.armigera dan S. litura serta gejala mikosis pada ulat terinfeksi. Hasilpenelitian menunjukkan bahwa suhu inkubasi berpengaruh terhadap lajupertumbuhan N. rileyi. Pada suhu 23±1ºC N. rileyi tumbuh lebih cepat(7,42-8,23 mm/hari) pada semua komposisi media yang diuji (SMAY,SMAYK, SMAYB, dan MLNr) dibanding pada suhu 27±1ºC (0,99-1,26mm/hari). Produksi konidia N. rileyi lebih banyak pada suhu 27±1ºCdibanding pada 23 ± 1ºC, yaitu berturut-turut 24,7 x 10 8 konidia/ml dan17,9 x 10 8 konidia/ml masing-masing pada media SMAYK dan MLNr.Perbedaan komposisi media tumbuh tidak menyebabkan penurunanpatogenisitas pada konidia N. rileyi sebab mortalitas ulat H. armigeramaupun S. litura masing-masing mencapai 100%. Hasil penelitianmengindikasikan bahwa N. rileyi mudah diperbanyak secara massal padamedium agar dan virulensinya baik pada H. armigera dan S. litura.</p><p>Kata kunci : Nomuraea rileyi, epizootik, Helicoverpa armigera,Spodoptera litura, konidia, patogenisitas, mortalitas</p><p>ABSTRACT</p><p>Effect of medium composition on growth of entomo-pathogenic fungi Nomuraea rileyi (Farlow) Samson andits pathogenicity against Helicoverpa armigera andSpodoptera litura</p><p>N. rileyi is one of potential entomopathogenic fungi to controlcotton bollworm, Helicoverpa armigera, tobacco and Rhicinus caterpilar,Spodoptera litura. These fungi naturally infect those insect pests indicatingtheir potential to be used as natural control agent. Techniques of in vitroproduction of these fungi need to be developed to find out their potentialagainst the insect target. Study on effect of medium composition ongrowth of entomopathogenic fungi N. rileyi and its pathogenicity againstH. armigera and S. litura was carried out at Phytopathology and InsectPathology Laboratories of Indonesian Tobacco and Fiber Crops ResearchInstitute (IToFCRI) from May to November 2009. The objective of thestudy was to find out the suitable composition of medium for N. rileyi andits pathogenicity against H. armigera and S. litura. The study consisted oftwo tests. The first test was testing for biological characters, namely invitro growth rate and conidia production of N. rileyi on four differentcompositions of medium as followed: (1) Sabouraud maltose agar + yeastextract (SMAY), (2) Sabouraud maltose agar + yeast extract + rice extract(SMAYR), (3) Sabouraud maltose agar + yeast extract + potato extract(SMAYP), and (4) Completed medium for N. rileyi (MLNr). Alltreatments were designed in randomized complete design (RCD) with fivereplicates. Parameters observed were the growth rate of N. rileyi andconidia production. The second was testing on pathogenicity of N. rileyiproduced from all medium tested against H. armigera and S. litura larvae.Result showed that incubation temperature influenced the growth rate offungi. N. rileyi grew faster at 23±1ºC (7.42-8.23 mm/day) than that at27±1ºC (0.99-1.26 mm/day) on all media tested. Conidia production washigher at 27±1ºC than at 23±1ºC. Both SMAYP and MLNr were the bestmedia for producing N. rileyi conidia, which were 24.7 and 17.9 x 10 8conidia/ml, respectively. Pathogenicity of N. rileyi against H. armigeraand S. litura was not affected by composition of medium tested becausethe larval mortality of both insect pests was 100%. This study indicatedthat N. rileyi can be easily produced massively on agar media and it isvirulent against H. armigera and S. litura.</p><p>Key words : Nomuraea rileyi, Helicoverpa armigera, Spodoptera litura,conidia, in vitro, pathogenicity, mortality, epizootic</p>

scholarly journals PENGARUH UKURAN BRAKTEA BEBERAPA AKSESI KAPAS TERHADAP TINGKAT SERANGAN HAMA PENGGEREK BUAH Helicoverpa armigera (HUBNER)

2020 ◽  
Vol 13 (4) ◽  
pp. 125
Author(s):  
IG.A.A. INDRAYANI ◽  
SIWI SUMARTINI
Keyword(s):  
Helicoverpa Armigera ◽  
Morphological Character ◽  
Insect Pests ◽  
Block Design ◽  
Morphological Characters ◽  
Floral Bract ◽  
Randomized Block Design ◽  
Cotton Plants ◽  
American Bollworm ◽  
Helicoverpa Armígera

<p>ABSTRAK<br />Hingga kini teknik perakitan varietas kapas tahan hama masih<br />dilakukan secara konvensional berdasarkan beberapa karakter morfologi<br />tanaman, seperti: bulu daun, daun okra, braktea berpilin, nektar, dan<br />gosipol tinggi. Karakter-karakter ini diketahui erat hubungannya dengan<br />ketahanan terhadap hama, khususnya H. armigera. Berkaitan dengan<br />serangan H. armigera pada buah, diduga ada bagian-bagian buah kapas<br />yang berkontribusi secara langsung pada serangan hama ini, misalnya<br />braktea buah. Namun demikian, besarnya pengaruh braktea terhadap<br />kerusakan buah kapas perlu dipelajari dalam upaya meminimalkan<br />kerusakan. Penelitian ini bertujuan untuk mengetahui pengaruh ukuran<br />braktea terhadap tingkat kerusakan buah oleh H. armigera pada beberapa<br />aksesi kapas. Penelitian dilaksanakan di Kebun Percobaan Balai Penelitian<br />Tanaman Tembakau dan Serat, di Asembagus, Situbondo, Jawa Timur<br />mulai bulan Januari hingga Desember 2006. Sebanyak 18 aksesi dari 50<br />aksesi kapas dengan berbagai variasi ukuran braktea digunakan sebagai<br />perlakuan. Setiap perlakuan (aksesi) disusun dalam rancangan acak<br />kelompok (RAK), dengan tiga kali ulangan. Lima tanaman kapas dari<br />masing-masing aksesi ditentukan secara acak, dan sebanyak 5 buah kapas<br />muda (diameter ± 4 cm) dipetik dari masing-masing tanaman sampel,<br />kemudian dibawa ke laboratorium untuk diukur luas braktea dan buahnya.<br />Selain itu dilakukan pula pengamatan kerusakan buah dan hasil kapas<br />berbiji di lapang. Hasil penelitian menunjukkan bahwa ukuran braktea<br />berkorelasi positif dengan tingkat kerusakan buah (R 2 = 0,9014), sehingga<br />braktea berukuran besar dan lebar serta menutupi buah secara total<br />berpotensi mengalami kerusakan akibat serangan H. armigera lebih tinggi<br />dibanding braktea berukuran kecil dan sempit. Ukuran panjang dan lebar<br />braktea pada 18 aksesi kapas bervariasi antar aksesi dan masing-masing<br />berkorelasi positif dengan luas (R 2 = 0,876; R 2 = 0,894). Hasil penelitian<br />ini dapat dimanfaatkan dalam merakit varietas tahan hama, dan<br />kombinasinya dengan karakter-karakter morfologi kapas yang sudah ada<br />untuk menghasilkan varietas kapas baru dengan tingkat ketahanan yang<br />lebih tinggi terhadap hama penggerek buah H. armigera.<br />Katakunci : Braktea, Helicoverpa armigera, aksesi kapas, karakter<br />morfologi.</p><p><br />ABSTRACT<br />Effects of bract size of several cotton accessions to<br />American bollworm injury level<br />Conventional  method  by  crossing  technique  based  on<br />morphological characters of plant is now still used in providing resistant<br />varieties of cotton against insect bollworms. A number of genetic<br />characters are now available and have been studying for their assosiation<br />with insect pests resistance such as hairiness, okra leaf, frego bract,<br />nectariless, and high gossypol. Regarding to boll damage by H. armigera,<br />it can be mentioned that there are many other morphological characters of<br />cotton attributable to bollworm damage, such as floral bract. As a part of<br />boll, it is estimated that bracts assosiated with bollworm attacked due to<br />their larger size compared with boll size. Objective of the study was to find<br />out the effect of bract size in relation to bollworm damage on cotton<br />accessions. The study was conducted at Experimental Station of<br />Indonesian Tobacco and Fiber Crops Research Institute in Asembagus,<br />Situbondo, East Java from January to December 2006. Eighteen of fifty<br />cotton accessions were used as treatment and they were arranged in<br />Randomized Block Design (RBD) with three replications. Five randomly<br />cotton plants from each accession and five young bolls were sampled<br />from the selected plant with about 4 cm of diameter were brought in the<br />laboratory to collect information on bract and boll sizes. Bollworm<br />damage was determined by counting the damaged bolls in the field as well<br />as the seed cotton yield. Result showed that bract size was positively<br />correlated with boll damage (R 2 = 0.9014). Higher damaged bolls occured<br />on bolls which is covered completely by bracts. There is variation between<br />length and wide size of bracts among cotton accessions and both showed<br />positive correlation to bract area (R 2 = 0.876; R 2 = 0.894). Based on this<br />study, higher resistance of cotton variety against H. armigera will<br />possiblly be provided through combination between bract size and any<br />other morphological characters of cotton.<br />Key words : Floral bract, Helicoverpa armigera, cotton accession,<br />morphological character</p>

scholarly journals Potensi Nematoda Patogen Serangga Steinernema spp. dalam Pengendalian Hama Utama Tanaman Kapas

2016 ◽  
Vol 1 (2) ◽  
pp. 101
Author(s):  
Heri Prabowo ◽  
I.G.A.A. Indrayani
Keyword(s):  
Helicoverpa Armigera ◽  
Insect Pests ◽  
Soil Surface ◽  
Tenebrio Molitor ◽  
Pectinophora Gossypiella ◽  
Helicoverpa Armígera ◽  
Soy Bean Oil

<p>Steinernema spp. memiliki potensi untuk mengendalikan hama tanaman kapas seperti Helicoverpa armigera dan Pectinophora gossypiella. Steinernema spp. mampu menyebabkan mortalitas P. gossypiella dan H. armi-gera berturut-turut sebesar 31,6–55,4 dan 46,3–63,8%. Steinernema spp. memiliki kemampuan membunuh lebih baik pada P. gossypiella, sedangkan kemampuan reproduksi dalam inangnya lebih baik pada H. armi-gera. Steinernema spp. mampu menginfeksi serangga inang lebih baik pada stadium ulat lebih tua diban-dingkan stadium muda. Steinernema spp. dapat diproduksi secara in vivo dan in vitro. Produksi secara in vivo dapat menggunakan Tenebrio molitor, Tirathaba rufivena, dan Attacus atlas. Produksi secara in vitro dapat menggunakan usus ayam, lemak sapi, dan minyak kedelai. Perlu dikembangkan formulasi Steinerne-ma spp. yang murah dan efektif untuk mengendalikan hama di atas permukaan tanah. Selain itu diperlukan pencarian isolat Steinernema spp. yang virulen dan cepat membunuh hama sasaran.</p><p> </p><p>Steinernema spp. could be potentially used for controlling H. armigera and P. gossypiella on cotton. Steiner-nema spp. causes mortality on P. gossypiella and H. armigera 31,6–55,4 and 46,3–63,8% respectively. The nematode causes a higher mortality on P. gossypiella than on H. armigera, however, produces more juvenile infective on H. armigera than on P. gossypiella. Higher successful infections of Steinernema spp. occurs on late larval stadium than on early one. Production of Steinernema spp. can be in vivo using Tenebrio molitor, Tirathaba rufivena, and Attacus atlas; and in vitro using chicken intestinum, cow lipid, and soy bean oil. For effecttively use, this nematode need to be formulated especially for controlling insect pests on soil surface, as well as finding the more virulent isolates against the target insects.</p>

scholarly journals HELICOVERPA ARMIGERA-PEST ON TOBACCO PLANTS

2019 ◽  
pp. 539-545
Author(s):  
Vesna Krsteska
Keyword(s):  
Population Dynamics ◽  
Helicoverpa Armigera ◽  
Coccinella Septempunctata ◽  
Field Trials ◽  
Tobacco Budworm ◽  
Economic Losses ◽  
Tobacco Plants ◽  
Helicoverpa Armígera ◽  
Hyposoter Didymator ◽  
In The Beginning

Helicoverpa armigera Hubner is а migratory, cosmopolitan and polycyclic species. The pest is known as tobacco bollworm or budworm. The species is polyphagous and is an economically important agricultural pest. The studies were conducted on tobacco plants in the Experimental Field of the Scientific Tobacco Institute - Prilep during 2017/2018. Monitoring of population dynamics of H. armigera was performed during tobacco vegetation in a 10 -day period, using the method of examining 100 tobacco plants, with Zig-Zag review of pest scouting. The collected larvae were additionally fed and grown in a laboratory according to the standard laboratory methodology. Field and laboratory trials were carried out for control of H. armigera, with five insecticides/ active ingredients: Spinetoram (a.i. 250 g/kg)- 0.3 kg/ha, Indoxacarb (a.i. 150 g/L)- 0.3 L/ha, Metaflumizone (a.i 240 g/L)- 1 L/ha; Emamectin (a.i. 9.5 g/kg)- 2 kg/ha and Flubendiamide (a.i. 480g/L)- 250 g/ha. Larvae of tobacco budworm damage flowers, seed capsules and top tobacco leaves. The population dynamics of H. armigera showed that the species was present on tobacco from the beginning of July (when plants produce flowers) until the end of tobacco vegetation. The population was the most numerous in August and reached its highest level of density on 20th August in both years. In field trials, were determined five predatory species that fed with young larvae of H. armigеrа: Chrysopa formosa (Neuroptera, Chrysopidae), Chrysopa perla (Neuroptera, Chrysopidae), Chrysopa carnea (Neuroptera, Chrysopidae), Coccinella septempunctata (Coleoptera, Coccinellidae) and Adonia variegata (Coleoptera, Coccinellidae). In the beginning of October on tobacco plants we found parasitized larvae of H. armigera. In laboratory conditions parasitized larvae ate less and ceased developing at their 4th stage- L4. In each parasitized larva was developed one parasite species of Hyposoter didymator (Hymenoptera, Ichneumonidae). H. didymator is endoparasitoid wasp, and it lives on host tissues. According to field and laboratory trials during 2017/2018, all applied insecticides showed high efficacy in H. armigera control. The highest average mortality of 100% was caused by insecticides: Spinetoram, Indoxacarb and Emamectin. Flubendiamide had 97.5% efficiency in control of this pest, and the insecticide Metaflumizone 95.0%. This pest represents a significant challenge to tobacco filed and it produces high economic losses of tobacco seed each year. For the control of H. armigera, it is required constant monitoring of the lifecycle of the pest. One part of management strategy is to study parasitoids, predators and microorganisms and use them against H. armigera. Chemical control is still the most reliable and economic way of protecting tobacco crop from tobacco bollworm.

scholarly journals Nutritional indices and biochemical profile of Helicoverpa armigera [Hübner (1808)] on different groundnut genotypes

2021 ◽  
Vol 117 (1) ◽  
pp. 1
Author(s):  
Abdul Rasheed WAR ◽  
Barkat HUSSAIN ◽  
Suraj Prashad MISHRA ◽  
Rajendra S MUNGHATE ◽  
Hari C SHARMA
Keyword(s):  
Helicoverpa Armigera ◽  
Host Plants ◽  
Insect Pests ◽  
Transferase Activity ◽  
Biochemical Profile ◽  
Nutritional Indices ◽  
Important Indicator ◽  
Helicoverpa Armígera ◽  
Moderately Resistant ◽  
Resistant Genotypes

<p>Nutritional indices and biochemical profile of <em>Helicoverpa armigera</em> in response to feeding on different groundnut genotypes was studied. The moderately resistant genotypes were ICGV 86699, ICGV 86031, ICG 2271 and ICG 1697.  JL 24 was used as the susceptible check. Consumption index (CI), approximate digestibility (AD), efficiency of conversion of ingested food (ECI) and efficiency of conversion of digested food (ECD) were recorded. In addition, the activities of digestive and defensive enzymes of H<em>. armigera</em> were studied. <em>H. armigera</em> larvae showed significantly lower CI, AD, ECI and EDI when fed on moderately resistant genotypes than the insects fed on JL 24. Serine protease and trypsin activities were low in insects fed on resistant genotypes than the ones fed on JL 24. Further, insects fed on resistant genotypes showed significantly greater glutathione-S-transferase activity than the insects fed on JL 24. A reverse trend was observed for esterase activity. Similar trend was observed for total protein content of the insects. Thus, nutritional quality of host plants affects insect’s physiology and could be used as an important indicator of host plant resistance against insect pests and to understand the adaptation of insect pests, if any, to various genotypes/host plants.</p>

scholarly journals Fluctuation patterns of different developmental stages of Helicoverpa armigera (Lepidoptera: Noctuidae) on chickpea (Cicer arietinum) and their relationship with the environment

2005 ◽  
Vol 16 (4) ◽  
Author(s):  
Zahid Ali Shah ◽  
Muhammad Shahzad
Keyword(s):  
Relative Humidity ◽  
Environmental Factors ◽  
Helicoverpa Armigera ◽  
Relative Frequency ◽  
Developmental Stages ◽  
Frequency Of Occurrence ◽  
Pod Borer ◽  
Helicoverpa Armígera ◽  
Lepidoptera Noctuidae ◽  
Eggs And Larvae

The relative frequency of occurrence of different developmental stages of gram pod borer, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), and the dependence of its developmental stages on environmental factors, are crucial in the population management. The densities of eggs and larvae were low from December to mid-February due to prevailing cold. Owing to optimum environmental conditions, increasing densities were observed throughout March and they droppped again during the first week of April. The densities of eggs and different larval instars of H. armigera were significantly positively correlated with temperature, and significantly negatively correlated with the average morning relative humidity (RH;%) but not with the average evening RH (%).

scholarly journals Prediction of Helicoverpa armigera (Hubner) larval population using weather based forewarning model in soybean

2021 ◽  
Vol 21 (4) ◽  
pp. 494-498
Author(s):  
RAM MANOHAR PATEL ◽  
A.N. Sharma ◽  
PURUSHOTTAM SHARMA
Keyword(s):  
Helicoverpa Armigera ◽  
Training Dataset ◽  
Maximum Temperature ◽  
Validation Dataset ◽  
Larval Population ◽  
Pod Borer ◽  
Significant Difference ◽  
Helicoverpa Armígera ◽  
Predicted Values ◽  
Helicoverpa Armigera Hubner

Weekly larval populations of pod borer, Helicoverpa armigera (Hubner) collected from 20 districts of Maharashtra under Crop Pest Surveillance and Advisory Project (CROPSAP) during 2010-2015 were analyzed to work out the effect of weather variables on the incidence of this insect on soybean. The appearance of larva was observed throughout the soybean growing season, and the peak incidence was observed during third week of August to first week of September (34-35 SMW). The correlation analysis of the data revealed that larval population was significantly and positively influenced by the minimum temperature and rainfall of current week as well as previous two weeks. For the development of forewarning model, data for the period from 2010 to 2013 were used as training dataset and two year (2014-2015) data as validation dataset. The mean model used for forewarning the incidence of pod borer larval population was developed by using step-wise multiple regression analysis in polynomial form. The results of mean model revealed that the significant variables affecting the pod borer larval population in soybean were maximum temperature (current and 1st lag week), and rainfall (current week) and the model explained 48.93% variation. The pre-disposing conditions for the incidence of larvae have been worked out as maximum temperature ranging from 26.1 to 31.47 ºC and rainfall ranging from 6.63 to 141.46 mm with low or medium rainfall in previous weeks followed by high in current week. The model was validated with 2014-15 independent dataset with predicted R2 (R2 ) value 28.13%. Two sample t-test showed no Pred significant difference between observed and predicted values (p = 0.3691 > 0.05).

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