This is an open access article d istributed under the terms of Creative Commons Attribution-NonCommer cial-ShareAl ike 4.0 International License, which permits unrestricted non-commercial use, d istribution, and reproduction in any med ium, provide d the original author and source are credited. INTRODUCTION C oc on u t ( C o c o s n u c i f e r a ) , p a lm o f f a mily Arecaceae is an important plantation crop grown in India and the southern states viz., Kerala, Tamil Nadu, Karnataka and Andhra Pradesh constitute major area and production of coconut. In India, coconut is grown in an area of 2,150.89’000 ha with an annual production of 21,288.24 million nuts and productivity of 9897 nuts/ha (CDB, 2018- 2019). In Tamil Nadu, coconut is cultivated in 4,38,935.20 ha with 49,474 lakh nuts and 11,271 nuts/ha production and productivity, respectively (CDB, 2019-2020). Most of the human population in India depends on coconut directly or indirectly for their livelihood. Coconuts possess high nutritive value including minerals, vitamin B, copper, iron along with proteins and antioxidants. They have several health benefits and it is a multipurpose tree, as the whole parts of coconut are used in one or the other way. The coconut tree is infested by several insect pests throughout the year (Thampan, 1975). Recently, whiteflies pose serious threat to the coconut growers in the country. Rugose spiralling whitefly (RSW), Aleurodicus rugioperculatus Martin (Hemiptera: Aleyrodidae) originally known as gumbo limbo spiralling whitefly was reported first from coconut during 2004 in Belize, Central America (Martin, 2004), in South Florida, United States in 2009 (Stocks et al., 2012), in Changanassery, Kottayam, Kerala during 2016 (Shanas et al., 2016), Mangalore and Udupi of Karnataka in 2016 (Selvaraj et al., 2017) and in Pollachi tract, Coimbatore district, Tamil Nadu, in August 2016 (Srinivasan et al., 2016). A total of 118 hosts have been documented to be attacked by the RSW, including crops and weeds (Stocks et al., 2012). They deposit creamy golden eggs in a spiral pattern on the underside of the leaves. When the nymphs hatch, they begin sucking the plant sap from the underside of the leaves, releasing honeydew that falls Seasonal incidence, population dynamics and morphometric traits of exotic coconut whiteflies in southern Tamil Nadu Suriya S.1*, Preetha G.1, Balakrishnan N.1 and Sheela J.2 1Department of Agricultural Entomology, 2Department of Plant Pathology, Agricultural College and Research Institute, Killikulam, Vallanadu - 628252, Tamil Nadu, India *Corresponding author Email : suriyaento23@gmail.com ABSTRACT Survey was conducted at fortnightly intervals to assess the intensity of damage caused by the invasive whiteflies in coconut in the southern districts of Tamil Nadu viz., Thoothukudi, Tirunelveli, Tenkasi and Kanyakumari from December 2020 to August 2021. Among the four districts, Kanyakumari recorded the highest whitefly incidence (56.30%), whereas, Tenkasi showed the lowest infestation (48.83%). Two whitefly species viz., rugose spiralling whitefly, Aleurodicus rugioperculatus Martin and bondars nesting whitefly (BNW), Paraleyrodes bondari Peracchi were observed in all the surveyed districts. The rugose spiralling whitefly nymphs and adult populations were found to be highest in Kanyakumari (49.46 nymphs/leaflet; 36.99 adults/leaflet) and lowest in Tenkasi (32.76 nymphs/leaflet; 26.71 adults/leaflet). Similarly, the population of bondars nesting whitefly nymphs and adults were highest in Kanyakumari (35.31 nymphs/leaflet; 34.84 adults/leaflet), whereas, the lowest nymphal population was observed in Tenkasi (22.79 nymphs/leaflet) and adult population in Thoothukudi (24.19 adults/leaflet). In morphometric analysis, length and breadth of egg (0.24 ± 0.03 mm and 0.13± 0.02 mm), nymphal (0.83 ± 0.08 mm and 0.38 ± 0.04 mm), pupal (1.08 ± 0.09 mm and 0.70 ± 0.09 mm), adult (female: 2.59 ± 0.09mm, 1.71 ± 0.14 mm; male: 2.27 ± 0.21 mm, 1.30 ± 0.05 mm) was recorded for A. rugioperculatus and egg (0.15 ± 0.02 mm and 0.08 ± 0.01 mm), nymphal (0.46 ± 0.02 mm and 0.36 ± 0.02 mm), pupal (0.59 ± 0.16 mm and 0.41 ± 0.09 mm), adult (1.09 ± 0.08 mm and 0.73 ± 0.07 mm) for P. bondari. Keywords : Coconut, intensity of damage, morphometry, whiteflies Original Research Paper J. Hortic. Sci. Vol. 18(1) : 216-222, 2023 https://doi.org/10.24154/jhs.v18i1.2167 217 J. Hortic. Sci. Vol. 18(1) : 216-222, 2023 Seasonal incidence of exotic coconut whiteflies on the upper surface of the fronds below them (Josephrajkumar et al., 2016). The fungus Capnodium grows on the honeydew, giving it a charcoal black a ppear a nce tha t ma y be visible fr om dista nce (Chandrika et al., 2016) that affects photosynthesis and in turn reduction in the quality of nuts. Later in 2018, bondars nesting whitefly (BNW), Paraleyrodes bondari Peracchi was first identified in Kayamkulam, Kerala. It feeds on more than 25 host plants. (Chandrika et al., 2018) which is also creating menace in the coconut gardens of Tamil Na du r ec ent ly. T he nymphs a nd a du lts of P. bondari construct nesting chambers of woolly wax and the adults will be remaining on the nests for egg laying. The woolly wax nests will be seen on the under surface of the leaflets. Another invasive nesting whitefly, Paraleyrodes minei laccarino was observed in coconut gardens in larger areas along the Western Ghat coastal regions of Kerala and Karnataka since November 2018 (Sujithra et al., 2019). Palm infesting whitefly, Aleurotrachelus atratus Hempel was first reported on ornamental areca palm in 2019 at Mysore and Mandya districts of Karnataka (Selvaraj et al., 2019). At present, the whitefly complex in coconut pose serious threat to the growers as the under surface of leaves were totally covered with whiteflies and the sooty mould infestation dominates the upper surface. Coconut is an important crop in the southern districts of Tamil Nadu and the incidence of whiteflies can cause stress to the plant by removing nutrients and water. In addition to damaging the host plants, whiteflies also create a nuisance in the area of infestation. In this context, the present study was undertaken to a sses s the sea sona l incidence a nd popula tion dynamics of whitefly species in southern regions of Ta mil N a du a nd t o s t u dy the mor p homet r ic parameters of exotic whiteflies of coconut. MATERIALS AND METHODS Surveys were conducted at fortnightly intervals in the southern districts of Tamil Nadu viz., Thoothukudi, Kanya kuma ri, Tir unelveli a nd Tenkasi on five locations of each district from December 2020 to August 2021 to assess the incidence and population dynamics of whitefly species. The seasonal incidence and the population dynamics of coconut whiteflies was assessed on the under surface of 100 leaflets randomly on ten palms each in five locations. The intensity of damage was calculated using the following formula as suggested by Elango et al. (2019). No. of fronds infested / tree Intensity of damage (%) = ———————— x 100 Total no. of fronds observed/ tree The adult whiteflies were caged on potted coconut plants leaf for oviposition and freshly laid egg spirals were identified for A. rugioperculatus and the nests were observed for the eggs of P. bondari. The eggs were observed regularly and the immature stages of whiteflies were excised daily and measurements on eggs, nymphal stages, pupae and adults were made using LEICA S8 APO with image analyser. The data obtained on the intensity of damage and populations of A. rugioperculatus and P. bondari were statistically analysed using SPSS version 16.0 software. RESULTS AND DISCUSSION Survey on the incidence and population dynamics of coconut whiteflies in the four southern districts of Tamil Nadu revealed that among the different species of whitefly inhabiting coconut the two whitefly species viz., rugose spiralling whitefly, A. rugioperculatus and bondar’s nesting whitefly, P. bondari were prevalent in Thoothukudi, Tirunelveli, Tenkasi and Kanyakumari districts. The intensity of damage, nymphal and adult popula tion of coconut whiteflies a nd their morphometric parameters are detailed here. Intensity of damage (%) by coconut whiteflies The distribution and severity of A. rugioperculatus and P. bondari in the southern districts of Tamil Nadu from December 2020 to August 2021 are presented in Table 1. The highest whitefly infestation (56.30%) was recorded in Kanyakumari followed by Tirunelveli (54.36%) and Thoothukudi (51.83%), whereas, Tenkasi district had the lowest infestation (48.83%). On considering the pest infestation in different months among the four districts, the highest infestation was observed in March 2021 (54.44%) followed by December 2020 (54.20%). The per cent infestation was found to be low during August 2021 (47.78%). The survey results on the intensity of damage (%) revealed that the mean per cent infestation of coconut whiteflies among the different months ranged from 47.78 to 54.44% and the mean infestation of coconut whiteflies in different districts revealed that the highest damage wa s recorded in Kanya kuma ri distr ict 218 Suriya et al. of different months, the descending order of the nymphal population of A. rugioperculatus is as follows: Kanya kuma r i (49. 46 nymphs/lea flet) >Tirunelveli (44.01 nymphs/leaflet) >Thoothukudi (39.68 nymphs/leaflet) > Tenkasi (32.76 nymphs/ lea f let ) . T he nymp ha l p op u la t ion of A . rugioperculatus was found to be highest throughout the period of observation except April and June 2021 in Kanyakumari district and Thoothukudi district recorded highest population in April 2021 (51.24 nymphs/leaflet) and Tirunelveli district in June 2021 (46.11 nymphs/lea flet). The lowest population of 22.95 nymphs/leaflet was observed in Tenkasi district during August 2021. In the Table 1 : Intensity of damage by coconut whiteflies in southern districts of Tamil Nadu Location Intensity of damage*(% ) Mean Dec-20 Jan-21 Feb-21 Mar-21 Apr-21 May-21 Jun-21 Jul-21 Aug-21 Thoothukudi 53.24 50.59 52.30 54.27 51.69 53.89 50.46 52.46 47.59 51.83 (46.88) (45.34) (46.32) (47.46) (45.97) (47.24) (45.26) (46.41) (43.62) (46.06) Tirunelveli 55.10 54.91 54.78 55.84 55.55 54.62 54.57 53.76 50.15 54.36 (47.93) (47.82) (47.75) (48.36) (48.19) (47.65) (47.62) (47.16) (45.09) (47.51) Tenkasi 48.11 50.18 49.70 51.08 50.20 49.40 50.30 49.00 41.51 48.83 (43.92) (45.10) (44.83) (45.62) (45.12) (44.66) (45.17) (44.43) (40.10) (44.33) Kanyakumari 60.35 58.56 58.11 56.58 56.17 54.40 54.06 56.62 51.89 56.30 (51.07) (49.93) (49.67) (48.79) (48.56) (47.53) (47.34) (48.81) (46.08) (48.64) Mean 54.20 53.56 53.73 54.44 53.40 53.08 52.35 52.96 47.78 (47.45) (47.05) (47.14) (47.55) (46.96) (46.76) (46.34) (46.70) (43.72) SE(d) District =0.387; Month =0.580; D×M = 1.159 CD (P=0.05) District = 0.767; Month = 1.150; D×M = 2.301ns *Mean of five replications. Figures in parentheses are arc sine transformed values Table 2 : Population of Aleurodicus rugioperculatus nymphs in southern districts of Tamil Nadu Location Population of A. rugioperculatus nymphs/leaflet* Mean Dec-20 Jan-21 Feb-21 Mar-21 Apr-21 May-21 Jun-21 Jul-21 Aug-21 Thoothukudi 44.99 35.15 32.98 42.39 51.24 43.46 33.37 40.04 33.48 39.68 (6.71) (5.96) (5.78) (6.53) (7.19) (6.63) (5.80) (6.36) (5.80) (6.30) Kanyakumari 62.70 49.83 53.83 55.30 45.15 50.73 45.13 42.80 39.65 49.46 (7.89) (7.01) (7.33) (7.44) (6.71) (7.13) (6.70) (6.52) (6.28) (7.00) Tirunelveli 50.62 41.07 47.21 40.21 46.38 50.37 46.11 34.95 39.15 44.01 (7.02) (6.35) (6.75) (6.27) (6.72) (7.05) (6.69) (5.95) (6.28) (6.56) Tenkasi 40.94 31.24 26.82 36.35 39.90 35.08 28.54 32.98 22.95 32.76 (6.41) (5.60) (5.23) (6.07) (6.35) (5.96) (5.38) (5.78) (4.83) (5.73) Mean 49.81 39.32 40.21 43.56 45.67 44.91 38.29 37.69 33.81 (7.00) (6.23) (6.27) (6.57) (6.74) (6.69) (6.14) (6.16) (5.80) SE(d) District=0.133; Month =0.200; D×M = 0.398 CD (P=0.05) District =0.262; Month =0.394; D×M = 0.787ns *Mean of five replications. Figures in parentheses are transformed values (56.30%) followed by Tirunelveli district (54.36%). Ala ga r et al. (2020) assessed the intensity of infestation of A. rugioperculatus during June 2018 to March 2020, the severity of A. rugioperculatus infestation was substantially higher in Tirunelveli (70.50%) and Kanyakumari (75.70%) districts, respectively. The study results are also in line with the findings of Selvaraj et al. (2016) and Sundararaj et al. (2017) who reported that the severity of infestation of A. rugioperculatus ranged from 40-60% in coconut. Population of A. rugioperculatus nymphs The population of A. rugioperculatus nymphs in four different southern districts of Tamil Nadu is given in Table 2. On considering the overall mean J. Hortic. Sci. Vol. 18(1) : 216-222, 2023 219 pr esent study, it wa s obser ved tha t the mea n population of A. rugioperculatus was prevalent throughout the study period and this is in tune with the findings of Elango et al. (2020) who studied the population dynamics of a novel exotic whitefly species, A. rugioperculatus a nd their na tur a l enemies on five year old Chowghat orange dwarf coconut tr ees a nd found the popula tion of A. rugioperculatus on coconut throughout the year, and the observation recorded on a weekly interval b a s is s how ed t ha t t he p op u la t ion of A . rugioperculatus increased from the first week of July 2018 (130.8 nymph/leaf/frond) to a maximum during the first week of October, 2018 (161.0 nymph/leaf/frond) and then decreased to a minimum during April, 2019 (Elango et al., 2020). Population of A. rugioperculatus adults The adult population of A. rugioperculatus during the period of observation is presented in Table 3. The mean population of A. rugioperculatus adults varied from 29.50 to 34.60 adults/leaflet throughout the study period from December 2020 to August 2021. Considering the overall mean the highest pop ula tion of A. rug iope rcul atus a dult s wa s recorded in Kanyakumari district (36.99 adults/ leaflet) and the lowest population in Tenkasi district (26.71 adults/ leaflet). Population of P. bondari nymphs The nymphal population of P. bondari was found to be less when compared to A. rugioperculatus. The mean nymphal population of P. bondari was high in K a nya ku ma r i (3 5. 3 1 nymphs /lea f let) followed by Tirunelveli (31.70 nymphs/leaflet), Thoothukudi (25.31 nymphs/leaflet) and Tenkasi (22.79 nymphs/leaflet). The P. bondari nymphs was found to be maximum in December 2020 (32.78 nymphs/leaflet) followed by February 2021 with 3 0. 1 7 nymp hs / lea flet. Among t he months of observation, the least number of P. bondari nymphs was noticed during January 2021 (25.69 nymphs/ leaflet) (Table 4). Population of P. bondari adults The adults of P. bondari were found to be highest in Kanyakumari district similar to nymphs with a population of 34.84 adults/leaflet and followed by Tirunelveli district (30.80 adults/leaflet) and then by Tenkasi and Thoothukudi districts with a mean popula tion of 25. 05 a nd 24. 19 a dults/lea flet, r espectively (Ta ble 5). While consider ing the monthly mean, the adult population of P. bondari was highest in December 2020 with a population of 33.07/leaflet followed by May 2021 (30. 18 adults/leaflet). The lowest population of 25.01 adults/leaflet was recorded in July 2021. Morphometrics parameters of A. rugioperculatus and P. bondari Egg The rugose spiralling whitefly, A. rugioperculatus eggs were 0.24±0.03 mm length, 0.13±0.02 mm br ea dth a nd 0. 6 7±0. 07 mm dia met er a nd t he bondar ’s nesting whitefly, P. bondari eggs were 0.15±0.02 mm in length, 0.08±0.01 mm breadth and 0.37±0.06 mm diameter. Table 3 : Population of Aleurodicus rugioperculatus adults in southern districts of Tamil Nadu Location Population of A. rugioperculatus adults/leaflet* Mean Dec-20 Jan-21 Feb-21 Mar-21 Apr-21 May-21 Jun-21 Jul-21 Aug-21 Thoothukudi 30.13 35.67 27.88 31.86 28.30 38.69 30.58 22.83 26.75 30.30 (5.51) (5.99) (5.26) (5.67) (5.35) (6.25) (5.56) (4.74) (5.20) (5.50) Kanyakumari 41.48 35.45 41.41 33.94 40.94 33.01 31.39 35.91 39.38 36.99 (6.47) (5.99) (6.47) (5.86) (6.43) (5.78) (5.65) (6.03) (6.31) (6.11) Tirunelveli 38.76 34.70 32.12 35.07 32.10 31.16 34.47 33.50 32.66 33.84 (6.26) (5.92) (5.70) (5.95) (5.69) (5.61) (5.90) (5.82) (5.74) (5.84) Tenkasi 28.04 25.20 29.95 25.57 27.92 25.83 23.62 25.77 28.45 26.71 (5.33) (5.06) (5.51) (5.10) (5.31) (5.13) (4.90) (5.12) (5.38) (5.21) Mean 34.60 32.76 32.84 31.61 32.32 32.17 30.02 29.50 31.81 (5.89) (5.74) (5.73) (5.65) (5.69) (5.69) (5.50) (5.43) (5.66) SE(d) District=0.093; Month = 0.139; D×M = 0.278 CD (P=0.05) District =0.184; Month =0.276 ns; D×M = 0.551 J. Hortic. Sci. Vol. 18(1) : 216-222, 2023 Seasonal incidence of exotic coconut whiteflies 220 Nymph The first instar nymphs of A. rugioperculatus were 0.35±0.04 mm length, 0.24±0.01 mm breadth, and 1.14±0.29 mm diameter, second instar nymphs were 0.58±0.04 mm length, 0.27±0.01 mm breadth and 1.27±0.19 mm diameter, third instar nymphs were 0.83±0.08 mm length, 0.38±0.04 mm breadth and 2. 50±0. 35 mm dia meter a nd the four th insta r nymphs were 1.08±0.09 mm in length, 0.70±0.09 mm breadth and 2.93±0.28 mm diameter. The body measurements of P. bondari were 0.24±0.01 mm length, 0.16±0.02 mm breadth and 0.83±0.03 mm diameter for first instar nymphs, 0.35±0.04 mm length, 0.25±0.02 mm br eadth, 0.90±0.03 mm diameter for second instar nymphs, 0.46±0.02 mm length, 0.36±0.02 mm breadth and 1.11±0.17 mm diameter for third instar nymphs and 0.59±0.16 mm in length, 0.41±0.09 mm in breadth and 1.67±0.41 mm in dia met er f or f ou r t h ins t a r nymp hs , respectively. Fourth instar nymphs are considered as a pseudo pupal stage. Adult The length and breadth of adult male were 2.27±0.21 a nd 1. 30±0. 05 mm a nd the a dult female wer e 2.59±0.09 and 1.71±0.14 mm. In bondar’s nesting whitefly, P. bondari adult, the length and breadth were 1.09±0.08 and 0.73±0.07 mm, respectively (Table 6). The morphometric analysis on the developmental stages of A. rugioperculatus in coconut revealed that the present result is almost similar in length (mm) with the findings of Saranya et al. (2021). Table 4 : Population of Paraleyrodes bondari nymphs in southern districts of Tamil Nadu Location Population of P. bondari nymphs/leaflet* Mean Dec-20 Jan-21 Feb-21 Mar-21 Apr-21 May-21 Jun-21 Jul-21 Aug-21 Thoothukudi 29.72 22.11 24.99 28.08 26.55 21.54 27.45 22.21 25.18 25.31 (5.47) (4.72) (5.03) (5.33) (5.17) (4.66) (5.27) (4.66) (5.05) (5.04) Kanyakumari 40.58 32.07 39.31 31.23 37.79 31.04 34.46 37.70 33.63 35.31 (6.41) (5.70) (6.30) (5.63) (6.19) (5.61) (5.91) (6.18) (5.83) (5.97) Tirunelveli 35.90 28.97 32.02 33.02 32.41 30.75 31.31 29.43 31.54 31.70 (6.02) (5.39) (5.67) (5.78) (5.72) (5.57) (5.62) (5.46) (5.65) (5.65) Tenkasi 24.94 19.62 24.37 18.52 22.84 24.83 24.32 17.34 28.29 22.79 (5.03) (4.48) (4.98) (4.36) (4.83) (5.03) (4.97) (4.19) (5.36) (4.80) Mean 32.78 25.69 30.17 27.71 29.90 27.04 29.39 26.67 29.66 (5.73) (5.07) (5.50) (5.28) (5.47) (5.22) (5.44) (5.12) (5.47) SE(d) District=0.097; Month = 0.146; D×M = 0.292 CD (P=0.05) District =0.193; Month =0.290; D×M = 0.579ns Table 5 : Population of Paraleyrodes bondari adults in southern districts of Tamil Nadu Location Population of P. bondari adults/leaflet* Mean Dec-20 Jan-21 Feb-21 Mar-21 Apr-21 May-21 Jun-21 Jul-21 Aug-21 Thoothukudi 29.28 23.93 20.06 23.13 25.87 27.23 24.00 19.75 24.43 24.19 (5.44) (4.92) (4.49) (4.84) (5.12) (5.26) (4.94) (4.42) (4.98) (4.94) Kanyakumari 41.55 33.34 40.52 31.37 38.41 30.06 34.9 30.75 32.63 34.84 (6.47) (5.81) (6.40) (5.64) (6.24) (5.53) (5.95) (5.58) (5.75) (5.93) Tirunelveli 35.45 31.22 27.81 33.34 29.95 33.78 31.11 23.69 30.84 30.80 (5.98) (5.62) (5.30) (5.81) (5.51) (5.85) (5.61) (4.90) (5.59) (5.57) Tenkasi 25.99 21.42 25.93 19.21 23.73 29.64 23.88 25.86 29.80 25.05 (5.12) (4.67) (5.12) (4.43) (4.89) (5.48) (4.92) (5.12) (5.49) (5.03) Mean 33.07 27.48 28.58 26.76 29.49 30.18 28.47 25.01 29.43 (5.76) (5.25) (5.33) (5.18) (5.44) (5.53) (5.36) (5.01) (5.45) SE(d) District=0.090; Month = 0.136; D×M = 0.271 CD (P=0.05) District =0.179; Month =0.269; D×M = 0.538 *Mean of five replications. Figures in parentheses are transformed values Suriya et al. J. Hortic. Sci. Vol. 18(1) : 216-222, 2023 221 CONCLUSION From the present study it is concluded that the exotic whitefly species, viz. , RSW, Aleurodicus rugioperculatus and BNW, Paraleyrodes bondari were the prevalent whiteflies in southern tracts of Tamil Nadu in coconut. The population of these invasive species were found throughout the year. REFERENCES Alagar, M., Rajamanikam, K., Chinnadurai, S. and Yasmin, A. 2020. Surveillance, assessment of infestation, biology, host range of an invasive r ugose spir a ling whitefly, Aleurodicus rugioperculatus Martin and status of its natural enemies in Tamil Nadu. J. Entomol. Zool. Stud., 8(3): 2041-2047. Chandrika, M., Josephrajkumar, A., Singh, L. and Alpana, D. 2018. New distributional record of r ugose spir a lling whitefly on coconut in Kamrup and Nalbari districts of Assam. Indian Coconut J., 61: 19-21. Chandrika, M., Josephrajkumar, A., Vinayaka, H., Krishnakumar, V., Renjith, P., Anjali, A. and Chowdappa, A. 2016. Gradient out break and bio-suppression of spiralling whitefly in coconut gardens in South India. Indian Coconut J., 59: 9-12. Coconut Development Boa rd (2018-19). Ar ea , production and productivity of coconut in India. http:// www.coconutboard.nic.in/stat.html Coconut Development Boa rd (2019-20). Ar ea , production and productivity of coconut in India. http:// www.coconutboard.nic.in/stat.html Elango, K. and Nelson, S. J. 2020. Influence of intercrops in coconut on Encarsia guadeloupae Viggiani parasitization of Rugose Spiralling Whitefly Aleurodicus rugioperculatus Martin. Annals of Plant Prot. Sci., 28: 1-4. Elango, K., Nelson, S. J., Sridharan, S., Paranidharan, V. a nd Ba la kr ishna n, S. 2019. Biology, distribution and host range of new invasive pest of India coconut rugose spiralling whitefly Aleurodicus rugioperculatus Martin in Tamil Nadu and the status of its natural enemies. Int. J. Agric. Sci., 11(9): 8423-8426. Josephrajkumar, A., Mohan, C. and Krishnakumar, V. 2016. Parasitism induced bio-suppression of Table 6 : Morphometric parameters of developmental stages of Aleurodicus rugioperculatus and Paraleyrodes bondari Sl. No. Parameter Descriptions* Length (mm) Breadth (mm) Diameter (mm) A. rugioperculatus 1 Egg 0.24 ± 0.03 0.13 ± 0.02 0.67 ± 0.07 2 Nymph 1st instar 0.35 ± 0.04 0.24 ± 0.01 1.14 ± 0.29 2nd instar 0.58 ± 0.04 0.27 ± 0.01 1.27 ± 0.19 3rd instar 0.83 ± 0.08 0.38 ± 0.04 2.50 ± 0.35 4th instar 1.08 ± 0.09 0.70 ± 0.09 2.93 ± 0.28 3 Adult female 2.59 ± 0.09 1.71 ± 0.14 - Adult male 2.27 ± 0.21 1.30 ± 0.05 - P. bondari 1 Egg 0.15 ± 0.02 0.08 ± 0.01 0.37 ± 0.06 2 Nymph 1st instar 0.24 ± 0.01 0.16 ± 0.02 0.83 ± 0.03 2nd instar 0.35 ± 0.04 0.25 ± 0.02 0.90 ± 0.03 3rd instar 0.46 ± 0.02 0.36 ± 0.02 1.11 ± 0.17 4th instar 0.59 ± 0.16 0.41 ± 0.09 1.67 ± 0.41 3 Adult 1.09 ± 0.08 0.73 ± 0.07 - *Mean ± SD of 10 observations J. Hortic. Sci. Vol. 18(1) : 216-222, 2023 Seasonal incidence of exotic coconut whiteflies 222 coconut whitefly in Kerala. Kerala Karshakan, 4: 26-27. M a r t in, J . H . 2 0 0 4 . W hit ef lies of Beliz e (Hemiptera: Aleyrodidae). Part 1-introduction and account of the subfamily Aleurodicinae Quaintance & Ba ker. Mosca s blancas de Belice (Hemiptera: Aleyrodidae). Parte 1- introducción y descripción de la subfamilia Aleurodicinae Quaintance & Baker. Zootaxa, 681: 1-119. Saranya, M., Kennedy, J., Jeyarani, S., Anandham, R. a nd Bha r a thi, N. 2021. Life cycle a nd morphometry of Rugose spiraling whitefly, Aleyrodicus rugioperculatus Ma r tin (Hemiptera: Aleyrodidae) on coconut. J. Appl. Nat. Sci., 13: 100-104. Selvaraj, K., Gupta, A., Venkatesan, T., Jalali, S., Sundararaj, R. and Ballal, C.R. 2017. First record of invasive rugose spiraling whitefly Aleurodicus rugioperculatus Ma r tin (Hemiptera: Aleyrodidae) along with parasitoids in Karnataka. J. Biol. Control., 31: 74-78. Selvaraj, K., Venkatesan, T., Sumalatha, B. and Kiran, C. 2019. Invasive rugose spiralling whitefly Aleurodicus rugioperculatus Martin, a serious pest of oil palm Elaeis guineensis in India. J. Oil Palm Res., 31: 651-656. Shanas, S., Job, J., Joseph, T. and Anju Krishnan, G. 2016. First r eport of the invasive rugose spiraling whitefly, Aleurodicus rugioperculatus Martin (Hemiptera: Aleyrodidae) from the old world. Entomon., 41: 365-368. Srinivasan, T., Saravanan, P., Josephrajkumar, A., Rajamanickam, K., Sridharan, S., David, P., Natarajan, N. and Shoba, N. 2016. Invasion of the rugose spiralling whitefly, Aleurodicus rugioperculatus Ma r tin (Hemipter a : Aleyrodidae) in Pollachi tract of Tamil Nadu, India. Madras Agric. J., 103(10-12): 349-353. Stocks, I.C. and Hodges, G. 2012. The rugose spiraling whitefly, Aleurodicus rugioperculatus Martin, a new exotic whitefly in South Florida (Hemiptera: Aleyrodidae). Florida Department of Agriculture and Consumer Services, Division of Plant Industry, Aleurodicus rugioperculatus, pest-alert. pdf (Accessed 7 March, 2017). Sujithra, M., Prathibha, V., Hegde, V. and Poorani, J. 2019. Occur r ence of nesting whitefly Paraleyrodes minei Iaccarino (Hemiptera: Aleyrodidae) in India. Indian J. Entomol., 81: 507-510. Sundararaj, R. and Selvaraj, K. 2017. Invasion of r ugose spir a ling whitefly, Aleurodicus rugioperculatus Ma r tin (Hemipter a : Aleyrodidae): a potential threat to coconut in India. Phytoparasitica., 45: 71-74. Thampan, P.K. 1975. The coconut palm and its products. Cochin, Green Villa Pub. House. (Received : 12.09.2021; Revised : 03.01.2023; Accepted 17.01.2023) Suriya et al. J. Hortic. Sci. Vol. 18(1) : 216-222, 2023