Vol. 8(35), pp. 4466-4473, 12 September, 2013

DOI:10.5897/AJAR2012.2157 African Journal of Agricultural ISSN 1991-637X ©2013 Academic Journals Research http://www.academicjournals.org/AJAR

Full Length Research Paper

Demographic parameters of antonii Signoret (: ) on neem, cocoa and henna

Srikumar K. K.* and Bhat P. S.

Department of Entomology, Directorate of Cashew Research, Puttur -574 202, Dakshina Kannada, Karnataka, India.

Accepted 21 August, 2013

Helopeltis antonii is a polyphagous pest causing considerable economic damage for cashew in South India. Relative multiplication of H. antonii was studied on its three important alternate host plants; neem, cocoa and henna. Life tables and population parameters for the mirid were constructed based on unlimited food condition and a natural enemy-free environment. The preoviposition period was between 19 to 23, 20 to 23 and 17 to 21 days of pivotal age, respectively on neem, cocoa and henna. The survivorship (lx) of H. antonii for three hosts shows similar pattern with high mortality occurring during egg, nymphal growth particularly in the early instar which then gradually decreases throughout the life span. The life expectancy (ex) of H. antonii declined gradually with the advancement of growth development in all three host plants. The net reproductive rate indicating the total female births (Ro) was 43.8, 45.9 and 16.1; the population increased with a intrinsic rate (rm) of 0.1425, 0.1505 and 0.1218: and finite rate (λ) of 1.1531, 1.1624 and 1.1295 female per day and a generation was completed in 26.52, 25.42 and 22.81 days on neem, cocoa and henna, respectively. Percent contribution of different growth stages in stable age-distribution revealed that the immature stages (eggs and nymphs) contributed maximum.

Key words: Helopeltis antonii, neem, cocoa, henna, life table.

INTRODUCTION

The tea mosquito bug, Helopeltis antonii (: and become necrotic with gummosis (Sundararaju and Miridae) is a serious pest of cashew in the west coast of Sundarababu, 1996). The affected tree is witnessed as South India (Sundararaju and Sundarababu, 1999). In burnt-up appearance during severe outbreak condition. A cashew the pest often causes 30 to 50% yield losses summary of feeding damage and visible symptoms on through blossom blight, shoot necrosis and damage to cocoa is given by Stonedahl (1991). Typical feeding nuts and apples. Fletcher (1914) reported the occurrence damage appears as a discoloured, necrotic area or lesion of H. antonii on cocoa, cinchona, Persian neem, annatto around the point of entry of the labial stylets into the plant and mahogany. Other hosts like guava (Cherian, 1937; tissue that becomes darker with age as the tissue around Ayyar, 1940; Puttarudriah, 1952) cocoa (Abraham and the puncture dies. Infestations during the early stages of Remamony, 1979); neem (), henna fruit often set result in immature fruit drop. Damage on (Lawsonia alba), (Sundararaju, 1984) are also reported pods appears as dark, circular lesions usually hardening as alternate host of H. antonii. as scars on the husk. Heavy infestations can result in pod In neem, the nymphs and adults of H. antonii suck the malformation and premature drop. Brunt-up appearance sap from the shoots, resulting in lesions that coalesce can be distinguished in L. alba due to damage by H . antonii

*Corresponding author. E-mail: [email protected]. Srikumar and Bhat 4467

Figure 1. (a) H. antonii damage symptom on neem, (b) cocoa pod and (c) henna.

Life table studies have several applications including analyzing population stability and structure, estimating extinction probabilities, predicting life history evolution, detecting outbreak in pest species, and examining the

dynamics of colonizing or invading species. Life table information may also be useful in constructing population models and understanding interactions with other pests and natural enemies. The objective of present study is to develop life history information on H. antonii on the important alternate hosts viz., neem, cocoa and henna and to determine the population parameters including the survivorship and rate of increase of H. antonii population on these host plants. This information could be extremely valuable for the future development of IPM programs against H. antonii. Demographic study was conducted to provide information on the life table of H. antonii fed on neem, cocoa and henna. Population growth parameters pertinent to this species are furnished in the present study.

Figure 2. First instars nymphs on neem. MATERIALS AND METHODS

To construct the life table, the culture of H. antonii was maintained

under laboratory conditions in Department of Entomology, feeding (Figures 1 to 3). Directorate of Cashew Research, Puttur, Karnataka. Male and Life table parameters are important in the Female TMB, H. antonii were collected using long test tubes from measurement of population growth capacity of species cashew fields. Nylon mesh sleeve cages (170 cm height x 30 cm under specified conditions. These parameters are also diameter) were used to confine paired adult bugs on tender flushing used as indices of population growth rates responding to shoots of neem, cocoa and henna in the field. During the study selected conditions and as bioclimatic indices in period, range of field temperature was 16 to 38°C, humidity 90 to 98%, monthly rainfall 0 to 1187.8 mm and sunshine was 0.8 to 8.8 assessing the potential of a pest population growth in a h. Both ends of the cage were firmly tied to prevent the from new area. Fertility life tables are appropriate to study the escaping. The shoots were kept in their natural position by tying the dynamics of insect populations as an intermediate upper part of the sleeve cage to a stake and lower part to the twigs. process for estimating parameters related to the The sleeve cages were labeled with oviposition date and population growth potential, also called demographic precautions were taken to prevent from attacking the mirids. The presence of a pair of fine terminal respiratory filaments parameters. Earlier life table studies of H. antonii was projecting from the surface of the plant tissue was indicative of the performed on cashew (Siswanto et al., 2008); neem, presence of eggs embedded in the bark (Figure 3a). The caging guava and cashew (Sundararaju and Sundarababu, 1998). was done in the laboratory from fifth to seventh day after oviposition 4468 Afr. J. Agric. Res.

Figure 3. (b) Eggs deposited on cocoa shoots and (c) adult bug feeding on cocoa pod.

1.00 lx) when grown in limited spare. Life expectancy at age x (ex) gives neem 0.90 the average remaining lifetime for an individual (Carey, 1993). Life 0.80 cocoa expectancy was computed by using the method suggested by Deevey (1947) and Atwal and Bains (1974). 0.70 henna

0.60

0.50 RESULTS AND DISCUSSION 0.40

0.30 The survivorship (lx) of H. antonii for three hosts (Figure Survival (lx) rate Survival 0.20 4) in general shows similar pattern with high mortality 0.10 occurring during egg and nymphal stages particularly in 0.00 0-5 5-10 10-15 15-20 20-25 25-30 30-35 35-40 40-45 the early instar which then gradually decreases Age (days) throughout the life span. This survivorship curve which

indicates a modest rate of mortality during early life Figure 4. Survivorship curve of H. antonii on neem, cocoa and stages and comparatively a gradual reduction as it henna. approached adulthood, the population assumed a near Type III diagonal survivorship curve following the

classification of Pearl (1928); Schowalter (2006) and to prevent nymphal migration. Immediately after hatching the 20 Speight et al. (1999). The H. antonii reared on cashew nymphs (Figure 2) of 5 batches each were individually reared on nearly exhibited Type II age-specific survivorship curve neem, cocoa and henna in nymphal rearing cages (size: 15×15×20 (Siswanto et al., 2008). cm and thickness: 18 gauge) (Sundararaju and John, 1992). Close perusal of the figures (Figures 5 to 7) indicates Nymphal rearing cages consisted of four glass vials of 5 ml capacity fixed on a small aluminum stand with a handle of 15 cm height fixed that preoviposition period was between 19 to 23, 20 to 23 at the centre. The fresh neem and henna shoots kept in water filled and 17 to 21 days of pivotal age on neem, cocoa and vial were supplied in alternate days as feed. In case of cocoa, henna, respectively. The female contributed the highest nymphs were individually reared on cocoa pods (as nymphs shown number of progeny (mx) on 27, 26 and 23 days of life high mortality on cocoa shoots). The presence of exuviae was used (along with adult emergence), respectively on neem, to determine nymphal instars of the insect. In the rearing cage on cocoa and henna. The results of Siswanto et al. (2008) the two sides, provisions were made to fix with cloth sleeve in order to facilitate the removal of adults after final moulting. showed that H. antonii fed on cashew laid highest The mated adult females were reared from egg stage on numbers of eggs on 36 days. It would be plausible that respective hosts and allowed to oviposit in the same host plant, that insect’s growth, longevity and reproduction could be is, the adults that emerged on particular day were paired and influenced by their food sources (hosts plants) and released in separate nylon mesh sleeve cages (170 cm height × 30 environmental conditions (Satpute et al., 2005; Ellers-Kirk cm diameter) in field. Fecundity of females was recorded until all of and Fleischer, 2006). them died. The total number of eggs laid on each day was recorded for each subgroup. Then, the number of eggs laid per female was Table 1a to d summarizes the population and reproductive dived by 1.80 (Female (F): Male (M) ratio = 1:0.80) for neem, 1.1 parameters of H. antonii. The gross reproductive rate (F: M = 1:1) for cocoa, 1.67 (F: M = 1:0.67) for henna in order to get (GRR) was 53.9, 90.0 and 41.9 on neem, cocoa and the number of female (mx). Observations from hatching of eggs till henna, respectively. The net reproductive rate (Ro), that the emergence and death of adults were recorded daily which is, one alive female egg would on the average replaced provided the values for life table (lx). Life tables were constructed according to the methods of Birch (1948), Howe (1953) and Atwal by daughter eggs of 43.8, 45.9 and 16.1 on neem, cocoa and Bains (1974). Stable age distribution was worked out by and henna, respectively. The mean length of corrected observing the population schedule of birth and death rate (mx and generation time (T) was 26.52, 25.42 and 22.81 days on Srikumar and Bhat 4469

Age specific survival Age specific fertility 1.2 18 16 1.0 14 0.8 12 10 0.6

8

specific survival survival specific

specific fertility fertility specific -

- 0.4 6 Age Age 4 0.2 2 0.0 0 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39

Pivotal age (d)

Figure 5. Age-specific survival and fecundity of H. antonii on neem.

Age specific survival Age specific fertility 1.2 20 18 1.0 16 0.8 14 12 0.6 10 8

specific survival specific 0.4

- 6

speicific fertility speicific -

0.2 4 Age Age

2 Age 0.0 0 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 Pivotal age (d)

Figure 6. Age-specific survival and fecundity on H. antonii on cocoa.

Age specific survival Age specific fecundity 1.2 20 18 1.0 16 0.8 14 12 0.6 10

specific survival specific 8 - 0.4 6

Age Age 4 0.2 fecundity specific Age 2 0.0 0 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 Pivotal age (d)

Figure 7. Age-specific survival and fecundity of H. antonii on henna. 4470 Afr. J. Agric. Res.

Table 1a. Life table of H. antonii on neem, cocoa and henna.

Parameters Formula Neem (shoots) Cocoa (pods) Henna (shoots) Gross reproduction rate (GRR) 53.9 90.0 41.9 (females/female/generation)

Net reproduction rate (Ro) 43.8 45.9 16.1

Mean length of generation (Tc) 27.92 26.52 23.7

Innate capacity of increase in 0.1354 0.1442 0.1173 numbers ( rc) females/female/day)

Arbitrary ‘rm’ (rc) 0.11 and 0.15 0.12 and 0.16 0.09 and 0.13

Intrinsic rate of increase, r m 0.1425 0.1505 0.1218 (females/female/day)

Corrected generation Time 26.52 25.42 22.81 (T)(days)

Finite rate of Increase in numbers, 1.1531 1.1624 1.1295 (λ) females/female/day

Doubling time, DT(days) 4.84 4.59 5.68

Hypothetical F2 Females 1918.44 2106.81 259.21

Stable age distribution Egg 57.5 60.82 57.85 Nymphs 36.6 32.98 36.42 Adults 5.9 8.24 5.71

Table 1b. Determination of rm value for H. antonii on Table 1d. Determination of rm value for H. antonii on neem. henna.

Arbitrary rm Difference Arbitrary rm Difference 0.11 0.15 0.04 0.09 0.13 0.04 2.1500 0.7374 1.4130 1.9386 0.7589 1.1797

= 1, that is, 2.15- 0.7374 = 1.4130, 2.15-1 = = 1, that is, 1.9386-0.7589 = 1.1797, 1.9386-1 = 1.1500. For 0.04, difference is 1.4130, difference will be 0.9386. For 0.04, difference is 1.1797, difference will be 1.15x 0.04/1.4130 = 0.0325 therefore corrected rm will be, 0.9386x 0.04/1.1797 = 0.318 therefore corrected rm will be, 0.11 + 0.0325 = 0.1425 females/female/day. 0.09 +0.0318 = 0.1218 females/female/day.

Table 1c. Determination of rm value for H. antonii on cocoa. neem, cocoa and henna, respectively. The population Arbitrary rm Difference increase at an infinitesimal rate (rm) of 0.1425 on neem, 0.12 0.16 0.04 0.1505 on cocoa and0.1218 on henna and respective 1.9600 0.6950 1.2650 finite rates (), that is, 1.1531, 1.1624 and 1.1295 per females per day were derived. The doubling time (DT) = 1, that is, 1.96-0.6950 = 1.2650, 1.9600-1 = was 4.84 for neem; 4.59 for cocoa and 5.68 for henna, 0.9600. For 0.04, difference is 1.26500, difference will be 0.96x 0.04/1.26 = 0.0304 therefore corrected rm will be, respectively. The hypothetical F2 females were worked 0.12 + 0.0304 = 0.1505 females/female/day. out to be 1840.41, 2106.81 and 259.21 on neem, cocoa Srikumar and Bhat 4471

Table 2. Life table for computing life expectancy of H. antonii reared on neem.

Number surviving Number Mortality rate per hundred Alive between age No. of the Expectation Developmental to the beginning dying alive at beginning of ‘x’ and ‘x+1’ individual’s life of further life stages of age interval ‘x’ days beyond ‘x’ age interval (x) ( ) ( ) (100 qx) ( ) ) Eggs 100 36 36.00 100.50 285.50 5.71

Nymph Instar 1 64.00 22.00 34.38 64.50 185.00 5.78 Instar 2 42.00 12.00 28.57 42.50 120.50 5.74 Instar 3 30.00 8.00 26.67 30.50 78.00 5.20 Instar 4 22.00 8.00 36.36 22.50 47.50 4.32 Instar 5 14.00 4.00 28.57 14.50 25.00 3.57 Adult 10.00 0.00 0.00 10.50 10.50 2.10

and henna, respectively. sources (host plants or host preys) (Siswanto et enough reserved food sources for the insects in The population parameters (Ro = 43.8, T = al., 2008). Life tables giving data on the rm of a the area during the lean period in cashew (May to

26.52, DT = 4.84) of H. antonii fed on neem was particular species provide insight into the September) would migrate to these alternate host lower than the population studied by Sundararaju characteristic life patterns of different species plants. It showed apparent in the study sites as and Sundarababu (1998; Ro = 65.63, T = 33.35, (Satpute et al., 2005). There is a range of innate alternate host plants were found at the vicinity of DT = 5.51). capacity for individual of a population (Dewitt, 1954; the cashew plantation including cocoa trees. This The H. antonii showed higher Ro, rm and λ Gill et al., 1989). suggests that appropriate management measures values and lower T (than neem) and DT on cocoa In the present investigation, the contribution made should be taken especially during vulnerable pods. It is generally presumed that shorter by different developmental stages viz., eggs, stages of cashew crop (flowering and fruiting development time and greater reproduction on a nymphs and adults of H. antonii towards stable period) before the onset of population build-up of host reflect the suitability of the plant tested (Van age distribution was 57.5, 36.6 and 5.9% on H. antonii. Lenteren and Nolbus, 1996). Also, this has been neem; 60.82, 32.98 and 8.24% on cocoa; and demonstrated in cotton where shorter generation 57.85, 36.42 and 5.71% on henna, respectively. time (T) favoured higher reproduction fitness The life expectancy data of H. antonii (Tables 2 to Conclusion (Trichilo and Leigh, 1985). 4) on neem, cocoa and henna indicates that it In spite of lower generation time T, the rm value declined gradually with the advancement of The demographic parameters obtained from H. was low on henna because of very low Ro value, development. Life expectancy increases for antonii reared on three host plants under i.e, H. antonii can multiply more rapidly on cocoa individuals who survive their risky egg hatching laboratory conditions are useful for the assessment and neem than on henna and also sustained period. of host plant quality. Intrinsic rate of increase and under unfavourable conditions on both the host H. antonii is a polyphagous insect which feeds on mean generation time reflect the suitability of the plants. H. antonii has a fine λ value (1.1295) on various host plants. Cashew is one of the major host host plant. Meanwhile, this study provides a henna; suggesting the importance of this host plants apart of neem, cocoa and henna. H. antonii foundation regarding the host range of H. antonii, plant for the pest. Insect’s growth, longevity and feeds particularly on the young and succulent and as such will be useful to pest management. reproduction could be influenced by their food parts of cashew. When cashew plants do not have The host plants examined in this study are all 4472 Afr. J. Agric. Res

Table 3. Life table for computing life expectancy of H. antonii reared on cocoa pods.

Mortality rate per hundred Number surviving Number Alive between No. of the Expectation Developmental alive at beginning of age to the beginning of dying age ‘x’ and ‘x+1’ individual’s life of further life stage age interval ‘x’ days beyond ‘x’ interval

(x) ( ) ( ) (100 qx) ( ) ) Eggs 100.00 46.00 46.00 100.50 254.50 5.09

Nymph Instar 1 54.00 19.00 35.19 54.50 154.00 5.70 Instar 2 35.00 14.00 40.00 35.50 99.50 5.69 Instar 3 21.00 4.00 19.05 21.50 64.00 6.10 Instar 4 17.00 3.00 17.65 17.50 42.50 5.00 Instar 5 14.00 4.00 28.57 14.50 25.00 3.57 Adult 10.00 0.00 0.00 10.50 10.50 2.10

Table 4. Life table for computing life expectancy of H. antonii reared on henna.

Number surviving to Number Mortality rate per hundred Alive between No. of the Expectation of Developmental the beginning of age dying alive at beginning of age ‘x’ and ‘x+1’ individual’s life further life stage interval days beyond ‘x’ ‘x’ age interval (x) ( ) ( ) (100 qx) ( ) ) Eggs 100.00 38 38.00 100.50 279.50 5.59

Nymph Instar 1 62.00 21.00 33.87 62.50 179.00 5.77 Instar 2 41.00 12.00 29.27 41.50 116.50 5.68 Instar 3 29.00 8.00 27.59 29.50 75.00 5.17 Instar 4 21.00 8.00 38.10 21.50 45.50 4.33 Instar 5 13.00 3.00 23.08 13.50 24.00 3.69 Adult 10.00 0.00 0.00 10.50 10.50 2.10

suitable for the pre-imaginable development of H. ACKNOWLEDGEMENTS sucking pests on horticultural crops, from the antonii, but the intrinsic rate of increase and the Indian Council of Agricultural Research (ICAR), net reproductive rate mark the cocoa as the most Our thanks are due to financial support received New Delhi. We thank the Director, Directorate of suitable host in terms of population increase. for the Out Reach Programme on management of Cashew Research for the encouragement and Srikumar and Bhat 4473

facilities.

Puttarudriah M (1952). Blister disease “Kajji” of guava fruits (Psidium REFERENCES guava). Mysore. Agric. J. 28:8-13. Satpute NS, Deshmukh SD, Rao NGV, Nimbalkar SA (2005). Life tables Abraham CC, Remamony KS (1979). Pests that damage cocoa plants and the intrinsic rate of increase of Earias vettela (Lepidopetra: in Kerala. Indian Arecanut Spices. Cocoa. J. 2(3):77-81. Noctuidae) reared on different hosts. Int. J. Trop. Insect Sci. 25:73- 79. Atwal AS, Brains SS (1974). Applied Ecology, Kalyani nd Publishers, Ludhiana, pp. 177-179. Schowalter TD (2006). Insect Ecology: An Ecosystem Approach, 2 Ayyar TVR (1940). Hand Book of Economic Entomology for South India. edition, Tokyo Academic Press, Japan. P. 572. Govt. Press, Madras. P. 528. Siswanto RM, Omar D, Karmawati E (2008). Life Tables and Population Birch LC (1948). The intrinsic rate of natural increase of an insect parameters of Helopeltis antonii (Hemiptera: Miridae) reared on population. J. Anim. Ecol. 17:15-26. cashew (Anacardium occidentale L.). J. Biosci. 19(1):91-101. Carey JR (1993). Applied demography for biologists with special Speight MR, Hunter MD, Watt AD (1999). Ecology of Insects: Concepts emphasis on insects. Oxford University Press, New York. P. 206. and Applications, Oxford, Blackwell Sciences Ltd. P. 350. Deevey ES (1947). Life table for natural population of . Rev. Stonedahl GM (1991). The Oriental species of Helopeltis (Heteroptera: Biol. 22:283-314. Miridae): a review of economic literature and guide to identification. Dewitt RM (1954). The intrinsic rate of natural increase in a pond snail Bull. Entomol. Res. 81:465-490. (Pirysa gyring Say). Am. Nat. 88:353-359. Sundararaju D (1984). Cashew pests and their natural enemies in Goa. Ellers-Kirk EC, Fleischer SJ (2006). Development and life table of J. Plantation Crops. 12(1):38-46. Acalymma vittatum (Coleoptera: Chrysomellidae), a vector of Erwinia Sundararaju D, John NJ (1992). Mass rearing technique for Helopeltis tracheiphila in cucurbits. Environ. Entmol. 35:875-880. antonii Sign. (Heteroptera: Miridae) - An Important pest of cashew. J. Fletcher TB (1914). Some South Indian Insects. Government Press, Plantation Crop 20(1): 46-53. Madras. pp. 488-489. Sundararaju D, Sundarababu PC (1996). Neem pest not a mystery. Cherian MC (1937). Administration report of the Government Nature 381:108. Entomologists, Coimbatore for 1936-1937. Rep. Dep. Agric. Madras. Sundararaju D, Sundarababu PC (1998). Life table studies of Helopeltis pp. 126-133. antonii Sign. (Heteroptera: Miridae) on neem, guava and cashew. J. Gill JS, Sidhu AS, Singh J (1989). A study to determine innate capacity Entomol. Research 22:241-244. for increase in numbers of Earias insulana (Boisd.) on cotton. J. Trichilo PG, Leigh TF (1985). The use of life tables to assess varietal Insect. Sci. 2:289-295. resistance of cotton to spider mites. Ent. Exp. Appl. 39:27-33. Howe RW (1953). The rapid determination of intrinsic rate increase of Van Lenteren JC, Noldus LPJJ (1996). Whitefly-plant relationship: an insect population. Ann. Appl. Biol. 40:134-155. Behavioural and ecological aspects. In D Gerling (ed.). Whiteflies: Pearl R (1928). The Rate of Living; being an account of some Their bionomics, pest status and management. Hampshire, England: experimental studies on the biology of life duration. Alfred A. Knopf Intercept Andover. pp. 47-89. Knopf, New York. P. 185.