<div>Background: Maruca vitrata is an economically important cryptic insect pest in pigeonpea. Caterpillar, the damaging stage hides in the webs thus escapes the contact with insecticides thus making an effective insecticide also ineffective. Hence, the role of some tall statured intercrops in the manipulation of pigeonpea crop environment for reducing the incidence of this webbing caterpillar was studied.&nbsp; 
 
Methods: Studies were conducted at NPRC, Vamban, Pudukottai dt., Tamil Nadu to study the effect of different intercrops in reducing the incidence of Maruca vitrata. During kharif 2016-17 and 2017-18, M. vitrata incidence was compared among the intercropping systems (pigeonpea with pearlmillet, sorghum and maize in 1:6 ratio) and sole pigeonpea crop. IPM modules were formulated in which botanical spray (NSKE 5% at bud initiation stage) and spray of recommended insecticide (indoxacarb 15.8 EC-0.7 ml/lt at flowering and 15 days later) were integrated with intercropping practice and tested for efficacy against this borer pest.&nbsp; 
 
Result: Intercropping of pigeonpea with pearlmillet was effective in managing the spotted pod borer. Coccinellids and spiders were more in intercropped pigeonpea than the sole pigeonpea crop. Synchronized flowering times of short duration pigeonpea and intercrops would have facilitated the transfer of natural enemies from intercrops to pigeonpea and this may be the one of the reasons for the lower insect population. IPM module I (pigeonpea intercropped with pearlmillet, NSKE and indoxacarb sprays) was effective in reducing the spotted pod borer damage. In IPM module I, yield of 770 kg/ha was obtained as against 550 kg/ha in sole pigeonpea crop. Among the IPM modules, high B:C ratio of 1:1.66 was recorded with IPM module I.</div>

​​Habitat Manipulation: An Important Component of IPM in the Management of Webbing Caterpillar, Maruca vitrata (Geyer) in Pigeonpea

<div>Background: Cowpea [Vigna unguiculata (L.) Walp.] is an important legume crop known for its nutritional value. However, the cultivation of this crop is greatly hampered by a destructive pest, a spotted pod borer (Maruca vitrata Fab.). Keeping the caustic nature of the pest in view, the present study was undertaken. 
 
Methods: Field evaluation of thirty cowpea genotypes was carried out by raising cowpea plants in an open field. Observations on the M. vitrata incidence were recorded at three days&rsquo; intervals starting from the development of the first buds to the end of flowering. Based on the level of infestation of buds, flowers and pods, the cowpea genotypes were categorised into four groups viz., resistant, moderately resistant, susceptible and highly susceptible. 
 
Results: Results of the study revealed a significant variation between the genotypes in terms of total damage (0.21 to 48.46%). Genotype IC 2918 recorded remarkably low damaged (0.12%) and was on par with Palakkadan thandan payar, Hridya, EC 300039, EC 101216, EC 98668, IC 39945, IC 52110, IC 39922 and IC 39916. The genotype Bhagyalaxmi recorded the highest damage (48.46%) followed by the variety Lola (30.04%). Flower buds were more susceptible to M. vitrata and suffered severe damage as compared to flowers and pods. Conversely, genotypes EC 98668 and IC 39922 were free from bud damage. Genotypes EC 300039, EC 98668, IC 52110, IC 39945, IC 2918 and IC 39922 recorded no flower damage and Palakkadan thandan payar, IC 39945, IC 2918 and IC 39947 recorded no pod damage.&nbsp;</div>

Screening of Cowpea Genotypes for Field Resistance to the Spotted Pod Borer (Maruca vitrata)

Legume pod borer, Maruca vitrata (Geyer) is one of the major constraints in increasing the production and productivity of grain legumes in the tropics. Keeping in view of the importance of this pest, present studies were carried out with the association of different morpho-chemical traits with resistance/susceptibility to M. vitrata at the Pulses Research Station, SDAU, S.K. Nagar. Some of the characters like flower colour, pod angle, protein, flavonoid, tannin and phenols were found to be associated with M. vitrata &nbsp;attack on cowpea genotypes. The pod damage by M. vitrata on different cowpea genotypes in the field ranged from 10.22 to 19.98%. High phenol content in pods (428.63mg/100g) and (326.33mg/100g) found responsible for the resistance of GC 5 and GC 0815, respectively and high flavonoid concentration in pods (484.08mg/100g) and (458.81mg/100g) in GC 5 and GC 0815 respectively were responsible for resistance. Based on these results, GC 5 and GC 0815 were categorized as moderately resistant. This paper discusses the physico-chemical traits associated with resistance to M. vitrata in cowpea variety/genotypes.&nbsp;

Morphological and bio-chemical factors associated with resistance to&nbsp;Maruca vitrata (testulalis) &nbsp;(Geyer) in cowpea

<div>Background: Legume pod borer or spotted pod borer, Maruca vitrata is one of the serious insect pest to the green gram, which causes damage mainly at the reproductive phase of the crop growth. The larvae of spotted pod borer are known to cause damage by webbing the leaves, bud, flower and pods together and feed from inside on them. Due to its webbing nature, it is very difficult to enter inside by natural enemies and chemicals cannot directly reach inside webbing. Host plant resistance to insect pests is an economically and ecologically preferred alternative as compared to other pest management tactics, particularly the synthetic pesticides. The present investigation was undertaken to examine the role of certain bio-chemical constituents of the immature pods of green gram in the expression of damage by the spotted pod borer. 
 
Methods: The experiments on screening were conducted during the kharif 2014 and 2015 at the Agricultural Research Farm, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi, (U.P.) to define the occurrence of M. vitrata on 20 promising varieties/genotypes of green gram. Pods were collected at the immature stage from different varieties/genotypes and biochemical constituents such as total soluble sugar, total chlorophyll, protein were estimated. 
 
Result: The maximum protein content was found in genotype IPM 306-6 (36.17 mg/g) and minimum in genotype PM-5 (20.53 mg/g). Highest total sugar content was reported from genotype ML 1256 (16.71 mg/g) and lowest total sugar content was recorded in PM-5 (10.94 mg/g).The phenol content in genotype PM-5 (9.00 mg/g) was significantly higher than others whereas, the minimum phenol content was reported in IPM 306-6 (5.14 mg/g). The higher amount of total chlorophyll content found in genotype IPM 306-6 (3.22 mg/g) and lowest in PM-5 (1.85 mg/g). The significant and positive correlation was observed between M. vitrata larval population, pod damage and protein (r=0.954** and r=0.952**, respectively) and total sugar content (r=0.986** and r=0.986**, respectively) and total chlorophyll content (r=0.994** and r=0.993**, respectively) in immature pods, while, the significant and negative correlation was found between phenol (r= -0.916** and r= -0.919**, respectively).</div>

<div>Biochemical Factors Associated with Resistance to Spotted Pod Borer, Maruca vitrata (Fabricius) in Green Gram</div>

<div style="text-align: justify;">The acute and persistent toxicity experiments was conducted in the Insectary of Agricultural College and Research Institute (AC&amp;RI), Maduari, Tamil Nadu Agricultural University. Two field experiments were conducted at farmer&rsquo;s field at Jadhi Goundanpatti, Attur Block, Dindigul district, Tamil Nadu. The incidence of M. vitrata (Geyer) has been increasing for the last few years and the larvae bore inside the flower buds, flowers and the green pods and cause upto 40-70 per cent damage. A new biological insecticide molecule, spinetoram 12 SC was evaluated for acute toxicity on laboratory reared M. vitrata population, and persistence on pigeonpea leaves at laboratory conditions; and effect on M. vitrata on pigeonpea at field conditions during 2012-13 and 2013-2014 seasons. Acute toxicity studies revealed that LC50&lsquo;s of spinetoram on third instar larvae after 24, 48 and 72 hours after treatment were 4.30, 1.95 and 1.46 ppm respectively. In persistence studies, Persistence was upto 11 DAT for spinetoram 12 SC 27 g a.i./ha, spinosad 45 SC 78 g, emamectin benzoate 5 SG at 11 g a.i./ha, and monocrotophos 36 SL at 500 g; and 14 DAT for spinetoram 12 SC 36 and 45 g a.i./ha. There was a reduction in the mortality of M. vitrata larvae as the time increased and there was no mortality at 21 DAT. Results indicated that spinetoram 12 SC was significantly effective at 36 and 45 g a.i./ha when sprayed thrice at 15 days interval and minimized the incidence of leaf feeder, M. vitrata on pigeonpea plants.&nbsp;</div>

Field evaluation of spinetoram 12 SC against Maruca vitrata on pigeonpea

<div>Background: Legume pod borer, Maruca vitrata (Fabricius), infests the Dolichos bean throughout the cropping season. However, there is no information on the seasonal abundance of M. vitrata over different seasons on Dolichos bean, which is an essential tool for forecasting and developing integrated pest management strategies.&nbsp; 
 
Methods: The seasonal abundance of M. vitrata on Dolichos bean were studied during three consecutive cropping seasons of 2019 Summer, Kharif and Rabi. The larval population in flowers and pods and the number of larval webbings and weather parameters were recorded and subjected to correlation and multiple linear regression analysis. 
 
Result: The overall larval abundance was observed to be higher in flowers than in pods. The highest larval abundance in flowers and pods was 14.60 and 13.40 during the 48th and 50th standard meteorological week (SMW) of Rabi 2019 respectively, which corresponds to 8 to 10 weeks after sowing (WAS) in flowers and 10 to 12 WAS in the case of pods. The number of larval webbings was higher, with 18.76 during the 49th SMW of Rabi 2019. The maximum temperature had a significant negative correlation with the larval abundance in flowers (r= -0.570), pods (r= -0.523) and the number of active webbings (r= -0.477). At the same time, the regression coefficient shows that rainfall had a significant negative influence on the larval abundance in pods (B= -1.26).</div>

Influence of Weather Parameters on the Seasonal Abundance of Legume Pod Borer Maruca vitrata (Crambidae: Lepidoptera) on Dolichos Bean (Lablab purpureus var. typicus)

<div style="text-align: justify;">The investigation on refinement and evaluation of artificial diet for M. vitrata, were carried out during 2014 and 2015 under walk in plant growth chamber established at ARS, Gulbarga, Karnataka, India. Comparison of developmental parameters of three successive generations of M. vitrata reared on different diets revealed that, maximum survival of egg, larva and pupa was 78.4 &plusmn; 3.1, 67.6&plusmn;5.5 and 73.0&plusmn;5.0 respectively in modified D-OOD diet and was superior over rest of the diets (D-OOD, D-New and D-OO) while it was on par with natural host plant. Maximum fecundity of 62.34&plusmn;4.1 eggs/female was observed in refined D-OOD diet was on par with pigeonpea host plant and superior over other diets. Biology studies of Maruca on refined artificial diet in comparison with natural host plant pigonpea were revealed that, incubation period (2.6 &plusmn; 0.46 and 2.85 &plusmn; 0.40 days), total larval duration (14.28&plusmn; 1.02 and 14.78&plusmn;1.52 days), pupal period (9.41&plusmn;0.70 days and 10.33&plusmn;1.08 days) did not vary significantly between modified diet and natural host. Fecundity in refined artificial diet was 66.00 &plusmn; 4.00 and it was 65.99&plusmn; 7.02 eggs on natural host plant. Per cent egg hatching was almost same in both the cases.&nbsp;</div>

<div style="text-align: justify;">Refinement and evaluation of artificial diet for rearing of legume pod borer, Maruca vitrata Geyer (Lepidoptera: Crambidae)&nbsp;</div>

Background: The spotted pod borer (SPB), Maruca vitrata Fabricius is a key insect pest of major legume crop i.e. pigeonpea, Cajanus cajan in India and semi-arid tropics. Identifying a SPB resistant genotype will help in sustainable management of SPB and in attaining nutritional security. The SPB has developed insecticide resistance to most of the chemical insecticide like Organophosphorous group of insecticides and also it is expanding its geographic limits. These factors are the driving forces for identifying tolerant genotypes for its sustainable management along with a suitable biorational.

Methods: Forty seven pigeonpea genotypes were screened during kharif 2015 to 2017 at ICAR-IIPR, Kanpur based on percent pod damage and Pest Resistance Susceptibility Rating (PRSR) under insecticide free condition. The 4 biorationals were tested against SPB in ICPL 87 along with untreated control in Randomised Block Design. Further the SPB molecular identity was confirmed by phylogenetic analysis of partial Cox 1 gene amplified from M. vitrata adult.

Results:&nbsp;Two indeterminate genotypes (Pusa2001 and Pusa33) as SPB resistant based on lowest mean pest resistance susceptibility rating (PRSR 1.7) The next best genotypes were a determinate (AL-15) and indeterminate genotype (LRG-30) with a PRSR of 2.0. The highest PRSR (6.0) was recorded from the ICPL 87, a susceptible check in the present experiment. Spinosad 45SC has recorded significantly lowest mean pod damage (6.67%) and highest mean yield (4.36kg/35m2) compared to 4 other treatments in the field efficacy trial. The phylogenetic analysis of Cox 1 gene from Kanpur population (KY559101) with 19 other M. vitrata populations in India revealed that it is more similar to Raichur population (KT070892) and it confirms M. vitrata has same ancestral homology in India.

&nbsp;

Assessing Pigeonpea Genotypes for Resistance against Maruca vitrata Fabricius and its Sustainable Management through Biorationals

Background: Maruca vitrata, commonly known as the legume pod borer, is a significant pest affecting leguminous crops like cowpea, pigeon pea, lab lab, beans, mung bean and others across tropical and subtropical regions. It severely reduces yields by boring into flowers, pods and seeds, causing significant damage. Field control failures with insecticides have been experienced by farmers due to development of insecticide resistance upon over reliance on insecticides. Hence, the present study attempted to quantify the levels of insecticide resistance and their detoxification routes in field collected populations of M. vitrata from intensive legume growing regions of India. 
 
Methods: In this study, a survey was conducted in intensive legume-growing regions of India to collect field populations of M. vitrata in 2024. Dose mortality bioassays were conducted against five commonly used insecticides (quinolphos, chlorantraniliprole, chlorpyrifos, flubendimide, indoxacarb) and resistance ratios were determined by comparing the LC50 values of field populations with the susceptible laboratory population. Enzyme assays were performed to evaluate the role of detoxifying enzymes like cytochrome p 450s, glutathione S-transferases and carboxylesterases in conferring resistance. 
 
Result: The resistance ratios varied from 56.48 to 311-fold for quinolphos, 3.84 to 97-fold for chlorantriniliprole, 15.76 to 92.088-fold for chlorpyrifos, 30.86 to 75.26-fold for flubendimide and 33.21 to 82.95-fold for indoxacarb. The activities of detoxification enzymes were significantly higher in the midgut of field collected M. vitrata larvae. The data suggests rational use of various insecticides in rotation so as to delay the further development of resistance in M. vitrata.

Field Evolved Insecticide Resistance in Legume Pod Borer, Maruca vitrata F. (Lepidoptera: Crambidae)

Background: The legume pod borer, Maruca vitrata, is recognized as serious insect pest on grain legumes and cause significant yield loss. Much research work has been carried out on management of M. vitrata with synthetic pesticides and biocides, there is paucity of knowledge on alternative non chemical methods to overcome this menace. Chemical signals from reproductive structures of host plants act as a key for lepidopteran phytophagous insects.&nbsp; 
 
Methods: Effects of volatiles from flowers and pods of different pulses such as pigeonpea, greengram, blackgram, cowpea and lablab on orientation pattern of M. vitrata larvae and adult moths and attractance behaviour of male moths to their females were investigated under laboratory conditions by using multi arm olfactometer and wide spaced basins.&nbsp; 
 
Result: One day old female moths showed significantly maximum orientation towards flowers of pigeonpea (42.7%) while elder age groups had the orientation ranging from 0.0 to 34.0 per cent on blackgram flowers and control (without host) respectively. The order of host preference of M. vitrata larvae observed as cowpea (32.2%) &gt;lablab (32.0%) &gt;pigeonpea (18.8%) &gt;greengram (9.0%) &gt;blackgram (4.8%) &gt;unsettled (3.0%). These results clearly showed the maximum preference of lablab by M. vitrata than other pulses tested. In an another experiment, one, two and three day old male moths had maximum orientation towards two day old females (31.3 to 40.0%) and this indicated more amount of sex pheromone emitted by female moths on two days after their emergence.

Habitat Manipulation: An Important Component of IPM in the Management of Webbing Caterpillar, Maruca vitrata (Geyer) in Pigeonpea

Screening of Cowpea Genotypes for Field Resistance to the Spotted Pod Borer (Maruca vitrata)

Morphological and bio-chemical factors associated with resistance to Maruca vitrata (testulalis) (Geyer) in cowpea

Biochemical Factors Associated with Resistance to Spotted Pod Borer, Maruca vitrata (Fabricius) in Green Gram

Field evaluation of spinetoram 12 SC against Maruca vitrata on pigeonpea

Influence of Weather Parameters on the Seasonal Abundance of Legume Pod Borer Maruca vitrata (Crambidae: Lepidoptera) on Dolichos Bean (Lablab purpureus var. typicus)

Refinement and evaluation of artificial diet for rearing of legume pod borer, Maruca vitrata Geyer (Lepidoptera: Crambidae)

Assessing Pigeonpea Genotypes for Resistance against Maruca vitrata Fabricius and its Sustainable Management through Biorationals

Field Evolved Insecticide Resistance in Legume Pod Borer, Maruca vitrata F. (Lepidoptera: Crambidae)

Orientation Behaviour of Legume Pod Borer, Maruca vitrata Fabricius (Lepidoptera: Crambidae) on Different Pulses