Introduction
Lassora (Cordia dichotoma L.) (Boraginaceae) is a tree of tropical and subtropical parts of the world. It is a medium sized tree with short twisted trunk, leaves simple, entire and slightly dentate, elliptical-lanceolate to broad ovate with round and cordate base, flower white, fruit drupe, yellowish brown, pink or nearly black when ripe with viscid sweetish transparent pulp surrounding a central stony part (Anonymous 2010). It grows well in sub-Himalayan region and outer ranges, climbing up to about 1500 m elevation (Singh et al. 2010).The immature fruits are pickled and also used as vegetable. The chemical composition of leaves of C. dichotoma indicate 12-15% crude protein, 16-28% crude fiber, 42-54% nitrogen free extract, 2-3% ether extract, 13-16% total ash, 2-4% calcium and about 0.3% phosphorus. It is used as medicine eg., immunomodulator, antidiabetic , diuretic, anthelminitic and hepatoprotective in folklore medicine etc. The chemical compostion of C. dichotoma seeds has disclosed the presence of α-amyrins, octacosanol, betulin, lupeol-3-rhamnoside, β-sitosterol, β-sitosterol-3-glucoside, hentricontane, hentricontanol, taxifolin-3, 5-dirhmnoside and hesperitin-7-rhamnoside (Srivastava, 2001). The presence of α-amyrin and toxifolin 3, 5, dirhamnoside in seeds show significant anti-inflammatory activity by an oral dose of 1gm/kg in albino rats (Singh et al. 2010). Moreover, the seeds of this plant reported to contain fatty acids and flavonoids (Srivastava, 2001). The yield of lassora is affected by many abiotic and biotic factors including insect pests. Among the insect which infest and cause heavy losses to the lassora, fruit weevil and gall forming insects are the most destructive. Larvae of fruit weevil bore into the fruits and shoots and adult attack the fruits and feed on the green pedicel, sepals and pollen grains inside the buds. The gall forming insects cause gall on leaves and tender stems (Orwa et al., 2009).
Galls appear on many different plants that are either caused by insects, mites, fungi, bacteria, or nematodes, however insect galls are the most common (Buss, 2008). Insects with the ability to induce galls consist of members of Coleoptera, Diptera, Thysanoptera, Hemiptera, Lepidoptera, and Hymenoptera with the aptitude to induce galls not consistent in all species. In the temperate latitudes, most of the insect-induced galls crop up on species of Asteraceae, Fagaceae, Salicaceae, Convolvulaceae, Malvaceae, Capparidaceae, Rosaceae and Euphorbiaceae (Meyer, 1987).
To date, more than 2,000 gall inducing insects have been identified in the United States, out of which more than l, 700 are gall midges or gall wasps. Galls are anomalous escalation of plant cells fashioned in response to egg-laying by adult insects or feeding by their young ones. They may arise at any place on the plant e.g. branches, seeds, flowers, petioles, stems or roots but most galls crop up on the leaves. Gall inducing species can cause physical or aesthetic damage to high valued plants by plummeting photosynthesis and seed production, fading foliage, altering plant architecture, causing defoliation, stem dieback, and rarely, death of plant (Buss, 2008).
Insects that are unable to create galls on plants, but feed on gall tissues induced by other species, are referred to as gall attackers (gall-feeders). Gall attacking weevils may have acquired their gall-feeding habits independently, whereas other gall attacking insects, such as inquilines gall wasps and gall midges may have evolved these habits from gall-inducing ancestors (Sugiura and Yamazaki, 2009).
Like the oligophagous cranberry weevil, Anthonomus musculus causes economic losses to blueberry because female deposit eggs into developing flower buds and subsequent larval feeding damages buds, which fail to produce fruit (Szendrei et al., 2009).
Similarly mango weevil which is a univoltine the females oviposit on immature fruits that are 1.9 cm in diameter or larger. Adult female carves out a cavity on the fruit surface and deposit an egg, which are immediately covered by a fruit exudates caused by the wound (Balock and Kozum, 1964).
Meanwhile the erythrina gall wasp causes the swelling on infected tissue parts while during severe infestation curling of young shoot, defoliation and death of tree occurs (Yang et al., 2004).
Objectives
Keeping in view the importance of lassora tree and the attack of fruit weevils and galls insects, present study was conducted to:
Observe seasonal outbreak of fruit weevil and gall forming insects in lassora.
Iidentify the time of infestation so that the control measures can be applied for better management of infestation.
Literature Review
The gall forming insects are universally highly developed groups with sophisticated biological and physiological organization that facilitated them to exploit their host plants more effectively and resourcefully than their non gall forming relatives. Espirito-Santo and Fernandes (2007) estimated the richness of gall forming insects in a worldwide context at about 133,000 species. Investigations on plant-herbivore interactions increased significantly in the last decades, particularly those concerning insect-host plant systems (Faria and Fernandes, 2001). Numerous hypotheses pertaining to the choice of the host plant and/or ovipositional site by the insect herbivore have been generated (Ferguson et al., 1991).
For insects, which have a short mobile phase and do not change location after oviposition choice, such as gall inducing insects, it appears that colonization of specific leaves or shoots within host is important, since not all plant parts can respond adequately to the insect attack (Whitham, 1980; Burstein and Wool, 1993). It has been proposed that natural selection would increase the preferential oviposition of insects during the co-evolution of plants and herbivore (Thompson, 1988). Indeed, most of the studies suggest that the choice of ovipositional sites by gall formers play a fundamental role for the development and survival of larvae within a population of host plants, or within an individual in that population (Whitham, 1980, 1983; Denno and McClure, 1983; Preszler and Price, 1988; Craig et al., 1989; Fernandes and Price, 1991) and even within a single leaf (Zucher, 1982).
Burstein and Wool (1993) argued that an insect should be able to assess the quality of potential host or site. Host selection has been verified experimentally in many studies (Leather 1985, Craig et al., 1989; Fritz and Nobel, 1989; Roininen and Tahvanainen, 1989). These choices can be made by the gall inducing female so as to maximize the nourishment of the larvae during its development (Rohfritsh, 1992) or to minimize microclimatic condition stresses (Edward and Wratten, 1980). Some other factors could also affect host selection, such as chemical defences (Bryant et al., 1983, Coley et al., 1985) or vigour of the plant module (Price, 1991).
A review of the hypotheses on the adaptive nature at galls is presented by Price et al. (1998). The extent of complexity in host architecture i.e., plant height, number of shoots and leaves and crown volume, is also known to influence directly the diversity and density of phytophagous insects (Vrcibradic et al., 2000), including galling insects (Espirito-Santo et al., 2007). Host plant spatial distribution could also affect the abundance of galls within a single individual (Aber and Melillo, 2001).
Different gall formers can attack the same vegetal species, causing the restructuring of species-speciï¬c characteristics (Hartley, 1998). The exploitation of the host plant by a gall maker can be so great that the latter assumes control of the gall tissue's chemical composition, which can be quite different from the ungalled tissue (Scareli-Santos, 2001). Some authors also have commented on the high level of speciï¬city of gall makers and host plant association (Mani, 1964; Abrahamson and Weiss, 1987).
Price (2005) reported the patterns of adaptive radiation illustrated by four groups of galling organisms: sawflies (Tenthredinidae: Hymenoptera) on willows (Salix, Salicaceae), gallwasps (Cynipidae) on oaks (Fagaceae), gall midges (Cecidomyiidae: Diptera) on a variety of host plants, and gall aphids (Fordinae: Homoptera: Pemphigidae) on Pistacia (Anacardiaceae). The ï¬rst three groups showed a similar pattern of radiation, with many species per genus sometimes sharing the same hosts. Species within taxa exploited different niches within a host plant by inducing galls on either leaves, stems, flowers or fruits. These same taxa have often diversiï¬ed into different host plants at the genus level.
Meyer (1987) studied the distributional pattern of gall forming insects and reported that in the temperate latitudes, most of the insect galls occur on the species of Asteraceae, Capparidaceae, Convolvulaceae, Euphorbiaceae, Fagaceae, Malvaceae, Rosaceae and Salicaceae. Raman's (2007) study on the diversity of gall forming insects indicated that the diversity of gall forming insects in the Indian subcontinent illustrated various peculiarities. Gall forming aphids, cynipids, and sawflies seem to be limited to the Himalayan slopes (28-33oN), while galling coccids and thrips crop up only in tropical peninsular India (8-23oN; 73-85oE). He further stated that the ability to induce galls among the identified insects of the Indian subcontinent is present in the Thysanoptera, Hemiptera, Diptera, and Hymenoptera. A warning, however, vestiges that numerous insects and gall bearing plants have not been resolute taxonomically.
Iyer (1989) studied the intensity of damage and susceptibility level of different mango varieties and found that significant variation in the intensity of damage and level of susceptibility to arthropods and pathogenic organisms existed among varieties of Mangifera indica. Iyer and Subramanyam (1993) documented that amongst the various M. indica infested by Cecidomyiids, only Procantarinia matteiana demonstrated a relatively worldwide circulation, irrespective of the faint metabolic discrepancies in different cultivars of M. indica . Pena and Mohyuddin (1997) noticed that almost 250 species of plant-feeding arthropods consume different organs of M. indica all over the world, out of that 26 species are confirmed gall inducers in the Indian subcontinent.
Singh (2000) studied the gall development phenomenon and reported that the galls appear through the alteration of vegetative auxiliary buds as the first nymphal instar consume the leaves and only the second nymphal instar migrate to the already structured galls. As a result of feeding by multiple neonate nymphs possibly causes the alteration of adjacent vegetative buds into galls, in approximately 30 days.
An increasing levels of endogenous auxin and a decrease in phenolic compounds and contents of auxin precursors e.g., tyrosine and tryptophan in the vegetative buds of mango caused the development of galls. Stone et al. (2001) reported that the divergence in the temporally regulated phenologies of flowers and leaves in susceptible host plant spp. could play a role in isolation of gall-inducing insect populations, thus facilitating divergence and diversification by genetic drift.
Singh (2003) also investigated the ovipositional behavior of galling arthropods and reported that the gravid females of gall inducing arthropods never laid eggs on the leaves of seedling. They preferred to lay on tender leaves of adult plants ready to produce flowers and fruits.
Cultural practices such as crop fertilization can affect susceptibility of plants to insect pests by altering plant tissue nutrient levels. Research shows that the ability of a crop plant to resist or tolerate insect pests and diseases is tied to optimal physical, chemical and mainly biological properties of soils (Altieri and Nicholls, 2003). Pablo et al. (2004) carried out experiment to see the effect of fertile soils on the incidence of gall forming insects. They argued that the fertile soils reduced the occurrence of gall forming insect species in plant communities. They found that 38 gall forming insect species specialized on their host plant species. The richness of gall forming insect species was negatively correlated with nitrogen and phosphorous availability.
Hansen et al. (1989) studied the distribution and life history of mango weevil, Cryptorhynchus mangiferae (Fabricius) (Coleoptera: Curculionidae), in Hawaii. The weevil was found on all major islands, but its distribution was not related to location on island, host plant density, cultivar, or other environmental parameters. Populations were sampled in a mango orchard at biweekly interval during the fruiting season. No differences were found in infestation rates among fruit in different vertical zones in the canopy. Head capsule width data suggested that there were more than five larval instars. Young larvae were first collected in mid-April while pupae and adults were first found at the end of May. More than one weevil can successfully develop in a seed.
Follett and Gabbard (2000) reported that mango weevil is a federally quarantined pest that prevents shipment of mangos from Hawaii, United States. Although this monophagous weevil allegedly causes reduced seed germination, damage to the fruit pulp, and premature fruit drop in mangos, Mango weevil is univoltine. Female oviposit on immature fruits that are 1.9 cm in diameter or larger. The adult female carves out a cavity on the fruit surface and deposits an egg, which is immediately covered by a fruit exudates caused by wound.
Follett (2002) investigated the effect of infestations of mango seed weevil, Sternochetus mangiferae (F.), on premature fruit drop of mangos. Mango fruits of equal size were collected both off the ground and from the tree at four times during the season. If weevil infested-fruit were more prone to dropping than uninfested fruit, the prediction was that a higher infestation rate would be found in fruit on the ground compared with the fruit on the tree. Average fruit weight was used as an indicator of fruit maturity. The seed infestation rate was significantly higher in fruit collected off the ground compared with fruit collected from the tree.
Bailez et al. (2003) reported that the guava weevil, Conotrachelus psidii Marshall, is severe pest of guava fruits in Brazil. The mated female lay eggs in small unripe fruits. As the fruits develop, so do the larvae. Mature larvae abandon the ripe fruits and pupate underground. Larval feeding causes extensive damage to the fruits.
Vantol et al. (2004) reported the vine weevil, Otiorhynchus sulcatus F. (Coleoptera: Curculionidae), is the polyphagous insect and an important pest in the production of hardy ornamental and small fruits world-wide. The vine weevil is a parthenogenetic reproducing species which forages for suitable host plants at night, but is found congregated in dark places during the day. Frass of this weevil species is suspected to contain attractive compounds that are host-plant related.
Inbar et al. (2004) reported that there is variability of gall forming insects in gall position, morphology, and complexity. Leaf galls can be found on many host plants. Leaf galls for example, can develop on the margin, blade, vein, or petiole. The galling habit probably evolved from related free feeding insects. The aphids seem to have evolved gradually towards better ability to manipulate their host plant.
Yang et al. (2004) reported that Erythrina gall wasp was first recorded damaging coral trees in Southern Taiwan in 2003, since then it has rapidly spread throughout the island on various species of Erythrina. Obvious swelling can be seen on infected tissue parts, and severe infestations cause curling of young shoots, defoliation, and death of the tree. At present, five species and a subspecies of coral trees have been recorded as suitable hosts.
Lanbert et al. (2007) described that two exotic gall fly species infest stems of native and exotic Phragmites australis. The distributions, presence, abundance of each fly species and their effects on flowering of native and exotic P. australis varied among sites. These species reduces the stem length and flowering rate.
Alvarado et al. (2008) described that galling insect species could directly affect leaf phenolic contents and indirectly affect the incidence and consumption of folivorous insects in tropical plant species. This may have important consequences on the preference of leaves by folivorous insects that might be excluded by galling insect species in dry tropical system.
Salle et al. (2009) founded the infested blow gum eucalyptus tree was in poor shape with heavy, hanging branches and twigs covered with galls. Galls consisted of multiple branches containing larvae and pupae, and could occur almost continually along branches. Several smaller branches and twigs were entirely dry with 10 to 20 mm cracks along galls.
Karuppaiah et al. (2010) reported that adult female of stone weevil lays the eggs on the stylar end of fruits and newly hatched grubs enter into seed by making puncture in endocarp at immature stage and starts feeding on soft seed coat and later it enters into endosperm moving downward. After entering the seed, it starts feeding on inner content of the seed, and pupates within the seed by making the hallow galleries. The weevil completes its life within a single fruit.
Stireman et al. (2010) reported that gall forming insects provide an ideal pathway to analyze the evolution of host insect interactions and understand the ecological interactions that donate to evolutionary diversification. Cecidomyiid flies present the largest radiations of gall inducin insects and characterized by complex trophic interactions with plants, fungal symbionts and the predators.
Materials and methods
The present study was carried out from April 2010-March 2011, in the experimental research area of University of Agriculture, Faisalabad. For sampling the seasonal outbreak of fruit weevil and gall formation on Lassora. Six trees were selected at different places in Faisalabad.
The trees were marked and regular visits were made to collect data on fruits and leaves. The two varieties (Lassora and Lassori) of the trees were marked.
Plan of work
The project was carried out by focusing on two aspects which were run simultaneously with one another. During the first aspect for sampling the population of larvae and adults of fruit weevil, 40 fruits were selected from each tree, which were include 10 fruits from each side of a tree; the fruits so collected from respective trees were placed in zip lock bags and brought to the laboratory. These fruits were dissected and observation on the presence or absence of fruit weevil was made.
Data on fruits were collected weekly and overall percentage infestation were recorded. After the fruit harvest weekly data was collected for knowing the time and season of invasion of fruit weevil on Cordia dichotoma. Invasion studies were specifically carried out regularly during the flowering time and as such flowers weree sampled for presence of eggs. The fruit formed from these flowers were sampled to find any of the stage of the fruit weevil in them.
The second aspect of study was include the percent infestation of galls on leaves. For this purpose, 40 leaves were sampled from each tree, including 10 leaves from each side. The number of galls present on each leaf of each side were recorded and comparison was made.
The data so collected was analysized statistically and weak link between the invasion of weevil and time of egg laying was identified.
Anonymous 2010. The Wealth of India, Raw Materials, A Dictionary of Indian Raw Material and Industrial Products, Vol 9, Council of Scientific & Industrial Research, New Delhi, 1950, 293-295.
ROLE OF CORDIA DICHOTOMA SEEDS AND LEAVES EXTRACT IN DEGENERATIVE DISORDERS Reena Singh*, Rahul Dev Lawania, Anurag Mishra, Rajiv Gupta. Volume 2, Issue 1, May - June 2010. International Journal of Pharmaceutical Sciences Review and Research
Srivastava SK, Srivastava SD, Taxifollin 3, 5-dirhamnoside from the seeds of Cordia dochotoma, Phytochemistry, Volume 18, 2001, 205-208.
