T. Boopathi

Genetic evidence for diversity of spiralling whitefly, Aleurodicus dispersus (Hemiptera: Aleyrodidae) populations in India

Abstract The spiralling whitefly Aleurodicus dispersus Russell (Hemiptera: Aleyrodidae), a highly polyphagous pest, has since about 2000 been an important pest of agricultural and horticultural crops in India. Despite its economic importance, little is known about the level and patterns of genetic variability in populations of the A. dispersus. In this study, we used the simple sequence repeats - polymerase chain reaction (SSR-PCR) technique was used to study the genetic diversity of A. dispersus in India. The present study is the first of its kind in India to utilize SSR markers for characterizing A. dispersus populations. A total of 356 different bands were scored using 18 primers for amplification. About 66.0% of alleles were polymorphic in A. dispersus populations. The SSR survey clearly detected moderate levels of polymorphism among the whitefly populations; multiple alleles were identified in many markers. The polymorphism information content (PIC) for SSR primers ranged from 0.0000 to 0.9541. Average genetic distances were estimated in our effort to investigate the level of DNA variation among the 7 geographic populations of A. dispersus from southern and northeastern India. The highest average genetic distance (0. 8182) was found between populations from Karnataka and Andhra Pradesh and Meghalaya and Mizoram. An UPGMA dendrogram based on similarity coefficients was constructed for the 7 populations analyzed. The A. dispersus population from Maharashtra was separated from those in the other 6 states viz., Tamil Nadu, Kerala, Andhra Pradesh, Karnataka, Mizoram and Meghalaya.

Microbial control of the exotic spiralling whitefly, Aleurodicus dispersus (Hemiptera: Aleyrodidae) on eggplant using entomopathogenic fungi.

Biological control using entomopathogenic fungi is a promising alternative to chemical control. The entomopathogenic fungi, Beauveria bassiana (Balsamo) Vuillemin, Metarhizium anisopliae (Metschnikoff) Sorokin, Lecanicillium lecanii (Zimmerm.) Zare and Gams and Isaria fumosorosea (Wize) were tested for their efficacy in controlling the spiralling whitefly, Aleurodicus dispersus Russell (Hemiptera: Aleyrodidae) on eggplant, Solanum melongena L. (cv. Pusa Purple Round) for two seasons in a randomized completely block design. Two applications of fungi were made at the rate of 2 × 109 conidia/mL. Observations on A. dispersus population were recorded on three leaves from the top, middle and bottom of 5 tagged plants per plot. I. fumosorosea and L. lecanii exhibited promising levels of control (>75% mortality) as compared to the other entomopathogenic fungi. I. fumosorosea was highly pathogenic to A. dispersus in both applications and seasons than other species of entomopathogenic fungi. Mortality from both seasons indicated differences in efficacy between days 3-15 after treatment. Application 2 produced the highest mortality in both seasons. Seasons had no influence on reduction of A. dispersus population. There is potential for use of entomopathogenic fungi to manage A. dispersus on eggplant. Key words: Aleurodicus dispersus, Solanum melongena, biocontrol, entomopathogenic fungi, mortality.

First report of economic injury to tomato due to Zeugodacus tau (Diptera: Tephritidae): relative abundance and effects of cultivar and season on injury

Abstract Insect infestation can adversely affect tomato (Solanum lycopersicum L.; Solanaceae) development and yield. Fruit flies (Diptera: Tephritidae) are a serious pest of tomato, and are spreading to areas where they were not previously found. This study was undertaken to determine if tephritid fruit flies were present, which species were most abundant, how tomato cultivars responded, and what amount of damage occurred in the Eastern Himalayas of India during May 2014 and 2015. Mature and ripe fruit (n = 20) per cultivar were picked at random from 12 cultivars at weekly intervals to assess percentage of infestation, fly species composition, larval infestation, pupal mortality, adult emergence, and sex ratio during 2 seasons. Seasonal fluctuation of male adults of Zeugodacus tau (Walker) (Diptera: Tephritidae) in tomato was studied by installing 3 modified clear traps, made from plastic bottles, that were baited with 0.5 mL Cue-lure and the insecticide dichlorovos 76% EC (Nuvan®). Survey and subsequent identification confirmed the presence of Z. tau in tomato in the Himalayas of India. This is the first report of the insect in the province, and of population outbreaks resulting in serious damage to tomato in India. Among fruit fly species present on tomato, Z. tau was more abundant (71.4–96.4%) in all geographical regions of Mizoram, India, than were Bactrocera correcta (Bezzi), B. dorsalis (Hendel), and B. latifrons (Hendel), which ranged from 3.6 to 28.6%. The highest percentage of infestation was in Champhai (72.7 ± 6.7%) and Kolasib (80.7 ± 3.5%) and the lowest in Mamit (14.7 ± 4.8%) and Serchhip (19.3 ± 4.7%). Cultivar influenced pupal mortality and adult emergence of Z. tau. Seasonal fluctuation of Z. tau males on tomato varied; the greatest numbers were trapped during May and Dec. Occurrence of Z. tau at high population densities was associated with high levels of damage and could lead to high economic losses in tomato fruit production.

Distribution and Biology of Mallada desjardinsi (Neuroptera: Chrysopidae) in India and Its Predatory Potential Against Aleurodicus dispersus (Hemiptera: Aleyrodidae)

Abstract In this study, we report the prevalence of Mallada desjardinsi (Navas) in seven geographical regions of India and provide the first report of its kind outlining the preying of all stages of the spiraling whitefly, Aleurodicus dispersus Russell, by M. desjardinsi. Sampling was conducted in seven regions of two provinces in India, Bengaluru (Karnataka) and Tiruppur (Tamil Nadu), which demonstrated that M. desjardinsi populations were most dense at the former and least at the later. To the best of our knowledge, this is the first report of its kind outlining observations regarding the biology and feeding potential of M. desjardinsi on A. dispersus under laboratory conditions. It was observed that the second nymphal stadium of A. dispersus was most preferred prey for M. desjardinsi and the least preferred was the A. dispersus adult. It was also seen that the third stadium of M. desjardinsi consumed more A. dispersus individuals than any other life stages. The longevity of female and the total developmental period of M. desjardinsi were computed as 27.6 ± 1.69 and 24.1 ± 0.99 d, respectively. The average total number of eggs laid by the M. desjardinsi female was 211.1 ± 6.35 eggs. M. desjardinsi was observed to be extremely efficient in terms of prey searching and predatory potential with respect to A. dispersus. The results of this study indicate strongly that M. desjardinsi has the potential to be used for the control of A. dispersus.

Microbial control of the invasive spiraling whitefly on cassava with entomopathogenic fungi

Abstract The entomopathogenic fungi Beauveria bassiana, Metarhizium anisopliae, Lecanicillium lecanii and Isaria fumosorosea were tested for their efficacy in managing the exotic spiraling whitefly Aleurodicus dispersus (Hemiptera, Aleyrodidae) on cassava (Manihot esculenta) during 2 seasons (2011-2012 and 2012-2013). The fungi I. fumosorosea and L. lecanii exhibited promising levels of control (> 70% mortality of the A. dispersus population). The percent mortality increased over time in both seasons. Application of I. fumosorosea was highly pathogenic to A. dispersus in both seasons compared to the other entomopathogenic fungi. Analysis of the percent mortality in both seasons revealed differences in efficacy between 3 and 15 days after treatment. The season also influenced the effects of the fungi on the A. dispersus population. Thus, entomopathogenic fungi have the potential to manage A. dispersus infestation of cassava.

Impact of postburn jhum agriculture on soil carbon pools in the north-eastern Himalayan region of India

Land-use change, particularly soil organic carbon (SOC) loss induced by shifting cultivation (jhum) is a common land degradation issue in the hilly tracts of the humid tropics. The SOC concentration comprises different pools (labile and recalcitrant fractions), and each fraction responds to temporal dynamics of adopted management practices at varying magnitudes, such as deforestation followed by cultivation. However, information on the variation of different SOC pools due to cultural practices of vegetation burning and postburn agricultural practices (crop production) associated with shifting cultivation remains inadequate. In the present investigation, we examined the effect of burning and postburning cultivation on SOC pools across different forest fallow periods at Kolasib district, Mizoram state of the north-eastern Himalayan Region of India. Results revealed increase in the soil C stocks and total organic carbon (TOC) due to the increase in the length of fallow periods ranging from 3 to 23 years. The TOC decreased significantly compared with antecedent concentrations before vegetation burning. This was mostly attributed to the reduction in contribution of active pools (very labile and labile) to TOC from 69% to 60%. However, contribution of passive pools (less labile and nonlabile) to TOC concentration increased from 31% to 40%. Postburn cultivation also resulted in reduction of TOC as well as considerable variation in the proportion of different SOC pools to TOC concentration. Among the different pools of SOC, the very labile C pool was most sensitive to land-use change induced by shifting cultivation (phytomass burning and postburn cultivation). The labile SOC pools can act as a sensitive indicator for devising suitable location specific management practices for restoration of soil health through SOC dynamics in degraded jhum lands in hilly ecosystems.

Bioactivity and traditional uses of 26 underutilized ethno-medicinal fruit species of North-East Himalaya, India

North-Eastern hill (NEH) region of India is considered as an agro-biodiversity hotspot, which has rich diversity of less-known, underutilized and ethno-medicinally important fruit crops. Since these fruits are ethno-medicinally and nutritionally important, we attempted to quantify the bioactive and antioxidant compounds of these underutilized fruit crops. The antioxidant properties were assayed by scavenging abilities using diphenyl-2-picrylhydrazyl (DPPH), azinobisethylbenzothiazoline-6-sulphonic acid (ABTS), assay of ferric reducing antioxidant power (FRAP), and determining total phenolics (TP) and total flavonoids (TF) contents. Soapberry (Sapindus mukorossi Gaertn.), Bengal quince (Aegle marmelos (Correa) Linn.), Elephant apple (Dillenia indica L.), Burmese grape (Baccaurea ramiflora Lour.), Amla (Emblica officinalis Gaertn.) and Chapalish (Artocarpus chama Buch.-Ham.) were high source of TP content; Elephant apple (D. indica L.) and Amla (E. officinalis Gaertn.) were found to be high source of TF. Highest DPPH, ABTS and FRAP activity of underutilized fruit crops were discussed. Significant positive correlation was detected among TF–FRAP, TF–ABTS, ABTS–FRAP, DPPH–FRAP and DPPH–ABTS assays. Principal component analysis was found an effective technique in grouping the local underutilized fruits based on their antioxidant contents. Results signify that, these underutilised fruits must be promoted for cultivation, pharmaceutical and processing use in large scale.

Collection and phenotypic characterisation of pole-type common bean (Phaseolus vulgaris L.) landraces from Mizoram

Common beans are one of the many important food legumes grown in India. In the hilly regions of north-eastern India farmers mostly grow the pole-type beans by intercropping beans with maize, and in backyardsand kitchen gardens. In this study, we characterized a set of 52 pole-type common bean landraces collectedfrom the state of Mizoram for 23 agro-morphological and quality traits. Remarkable variability was observedfor almost all the traits. Wide range of variability was found for the traits such as leaf length (7.5–18.0 cm), leafbreadth (6.2–12.8 cm) days to flowering (33–70 days), pods per plant (7.7–24.0), pod length (8.1–14.6 cm), podyield per plant (61.5–182.3 g), seeds per pod (4.6–8.0), 100-seed weight (23.0–50.1 g) and crude protein content(20–33.8%). Positively significant correlation coefficients were observed between 100-seed weight and daysto flowering; number of pods per plant and pod yield per plant. The patterns of morphological variation wereassessed using multivariate approaches. Five morphologically distinct clusters were identified within thecollected germplasm. The evolutionary grouping of the common bean landraces has been discussed consideringthe morphological features.