eChapters

Fruit borers : Criptophlebia illepida, Rapala varuna, Deudorix epijarbas, D. Isocrates : Lycaenidae

Of the four species, C.illepida is more damaging to litchi fruits. The larvae bore into developing fruits and seeds, filling the bore-holes with excreta and the infested fruits start rotting.

Shoot and fruit borer : Diaphania (Margaronia) caesalis :  Pyraustidae

The shoot-and fruit-borer D.caesalis is a major pest of jackfruit in India. The larvae are reddish brown with pale brown head and thin hairs from black warts. The caterpillars bore into the shoots, buds and fruits.  Affected shoots wilt or dry up and the fruits rot and drop. The adult is brown with grey elliptical patterns on the wings.

Spiralling whitefly : Aleurodicus dispersus : Aleyrodidae

A. dispersus originated from the tropical countries in Central and South America. More recently, it has been reported from Asia and Africa. In India, Andhra Pradesh, Karnataka, Kerala, Maharashtra and Tamil Nadu faces its problem. A. dispersus is a highly polyphagous species. Its wide host range includes many vegetable, ornamental and fruit crops, as well as numerous trees and shrubs, including Capsicum, Citrus, Cocos nucifera (coconut), Euphorbia pulcherrima (poinsettia), Glycine max (soybean), Hibiscus, Lycopersicon esculentum (tomato), Mangifera indica (mango), Musa (banana), Persea americana (avocado), Prunus spp., Psidium guajava (guava)and  Solanum melongena (brinjal) etc.

Grapevine stem girdler:  Sthenias grisator : Cerambycidae

This is a pest that can also survive on mango, rose, cocoa, coffee, almond, and mulberry. The ovipositing adult causes wilting of branches and then the entire vine. Adults are medium-sized, grey coloured beetles with a white spot at the center of each elytron. They are active at night.

Eggs are deposited in clusters of 2-4, underneath loose bark of girdled branches. Eggs are oval and enveloped in a white parchment like covering. Adults emerge out and start ovipositing individual eggs at a point in the vine in a circular fashion so that the vine dries up above this point. Egg period takes about 8 days. The grub has dark brown head and mouth has a pair of prominent mandibles, each with two teeth. The grub continues its life as a semi saprophyte and pupates in the same tunnel. A single generation can occupy one year.

Stem-borer: Batocera rufomaculata, B. rubus, Olenecamptus bilobus:Cerambycidae

These are large dark brown adult beetles that lay eggs in loose bark.  Grubs bore into the trunk and make tunnels in branches and main trunks.  This causes drying and wilting of the branches. Adults of O. bilobus are pale whitish with long serrate antenna.
 
When bark is suspected to have the grubs, try mechanical removal of them. Paste the tree trunk with mud paste containing insecticides like chlorpyriphos or carbaryl. In endemic areas, spray the bark with Carbaryl 4gm /l, Malathion one ml/l, or Chlorpyriphos 2.5ml/l

Mealy bugs: Ferrisia virgata, Planococcous lilacinus, P. pacificus, Maconellicoccus hirsutus, Perisopneumon ferox: Pseudococcidae

The fruit is seen covered with a mealy coating due to colonies of small reddish-white mealy bugs. They also infest leaves, shoots and buds. Due to sucking of sap by nymphs and adult female mealy bugs, fruits remain small in size and become shrivelled. Large number of mealy bugs is seen in the tip of the petiole abd also on the grooves of fruits epicarp. The fruit also becomes blackish due to the development of sooty mould.

Citrus butterfly: Papilio demoleus, P. polytes : Papilionidae

The pest is distributed all over the world and has a host range that includes citrus and other rutaceae plants like Aegle marmelos. Adult has the head and thorax black with a creamy-yellow coloration on the underside of the abdomen. Wings are dull black, orna-mented with yellow markings and a distinct red patch on the hind wing. The underside is orange and yellow coloured and can be seen when it flirts for honey collection or just before egg laying. The Antenna is black and clubbed.

Ber fruit fly:  Carpomyia vesuviana :Tephritidae

Adult is a small fly with black spots on the thorax and dark spots on the wings. They have only one pair of wings typical of diptera. The attack by the insect causes rotting of fruits and fruit drop. The adult female lays eggs singly in cavities made on the fruit by the ovipositor.  One female can lay up to 22 eggs. Egg period lasts for 2-3 days and the emerging maggots feed inside the fruit for about 7-10 days. The fully grown maggot falls to the ground to pupate in soil.  Pupal period is around 5-30 days. There can be 2-3 generations /year.

Pseudostem borer: Odoiporus longicollis: Curculionidae

Distribution : It is widely distributed in all banana growing areas and has got introduced into South India somewhere in the eighties and spread fast in the banana areas of Tamil Nadu, Maharashtra, Kerala and Karnataka.

Biology : Adults of the weevil are reddish brown to black and resemble the adults of the rhizome weevil in size and shape. They live for about four months. The snout is long with the characteristic geniculate antennae.

Indian gypsy moth: Lymantria obfuscata: Lymantridae

Eggs are laid by the bulky adult female moth, which has only rudimentary wings and hence cannot fly.  Eggs are laid under the bark on the tree trunks or on fallen leaves. They feed on many shade trees and other trees also.  Feeding is gregarious and done during night. The trees are almost completely defoliated. Management involves spot application of contact insecticides at the beginning, when the larvae are small and before they disperse to the different leaves.

Apple codling moth: Cydia (Carpocapsa) pomonella: Tortricidae 

This is an international pest and is now seen in Kashmir, Himachal Pradesh and Tamil Nadu. This is a fruit borer whose moth is silvery white with a dark band on the margin of the forewing and light brownish hind wings with a fringed margin. The moths hold their wings roof-like over the body while at rest.

This crop is gaining importance as a main ingredient in Indian diet due to its medicinal properties. Large areas are under its cultivation and the larger fruited varieties have become very popular. It is one of the prime constituents in ayurvedic preparations
Bark-eating caterpillars - Indarbela quadrinotata, I. tertraonis: Metarbelidae
The larvae of this species make zigzag galleries and feed on the bark under silken ribbon- shaped webs. They are stout and dirty brown in colour.
Fruit- borer : Deudorix Isocrates : Lycaenidae: The larvae of this beautiful butterfly cause considerable damage (up to 42%) to fruits.  They start feeding while the fruit is tender, and growing. During severe infestations, chemical control may be warranted. This can be done by spraying contact insecticides like malathion, or dichlorvos or  fenvalerate or other synthetic pyrethroids.

Green peach aphid/leaf curl aphid : Brachycaudus helichrysi : Aphididae

These are green aphids that suck the sap from growing buds. Leaf buds become weak and result in poor setting and premature fruit fall.

The pest has a worldwide distribution. In India it is seen in the hills of North India and in nilgiris.

It is a serious pest of peaches, plum, apricot, and almond. The aphids attack the tender portions like new buds, blossoms, petioles, tender fruits and leaves. When the new flushes are attacked, the leaves get curled and crinkled and fruit set is either reduced or  fruits fall off . The infestation starts with the commencement of bud swelling and continues until after flowering. The leaf curl may be confused with that due to the fungal leaf curl by Taphrina deformans.

Abstract

Geochemical processes occurring within the groundwater and reactions with aquifer minerals have a profound effect on water quality. Hydrogeochemical composition of groundwater can also be indicative of its origin and history of passage through underground materials which water has been in contact. Assessing groundwater quality and developing strategies to protect aquifers from contamination are necessary aspects for proper planning and designing water resources. Anthropogenic activities like explosion of population, industrial growth, inputs of fertilizer, pesticides, and irrigation has been a crucial factor for determining the quality of groundwater. In this scenario, 43 groundwater samples were collected from the Dindigul district of Tamilnadu, a Hard rock terrain. The samples wereanalyzed for major cations and anions along with heavy metals to derive the different quality parameters and to obtain the pollution indices of different samples. This study focuses to find out the spatial relationship between the analyzed fluoride concentration in groundwater and pollution indices derived from the heavy metal concentration in the groundwater of the study area and their variation with respect to season.

Abstract

Amongst all types of major land-use change, extending irrigated agriculture using a surface-water source has the greatest influence on groundwater – both significantly increasing recharge and changing water quality as excess irrigation water infiltrates into shallow aquifers. Hence, in order to understand the impact of the landuse on the groundwater system the study has been aimed to understand the process by adopting geophysical, geochemical and microbial analysis of groundwater samples. The study has been conducted in Chidambaram taluk, with a total area of 92.51Sq.km. A total of 39 groundwater samples were collected for the analysis of major cation and anion along with the microbial analysis, like Total Coliform, Total Viable Counts, Fecal coliforms, Vibrio cholera and Total Streptococci. The geochemical studies reveal that there is no correlation between these parameters and the microbial population. The migration of the water from the elevated regions (urban region) is witnessed and the concentration of the microbial population is higher in these regions except in the southern region which has impermeable clay and this arrest the movement of water.

Abstract

Groundwater is most favored as a source of drinking water in all over world. It is often thought to be cleaner and easier to treat when compared with surface water and as a result, many wells have been sunk. Uranium and other radionuclides in water can lead to health problems if present in higher concentrations. In order to study the behavior and to understand the influence of lithology in groundwater of Madurai district, a study was conducted by collecting a total of 216 samples of different seasons (Premonsoon, South west monsoon, Northeast monsoon and Post monsoon) with respect to lithology and the number of samples was depending upon their spatial coverage in the study area. The groundwater samples were analysed for U, Ca²⁺, Mg²⁺, Na⁺, K⁺, HCO₃^-, Cl^-, SO₄^2-, PO₄^3-, NO₃^-, F^-, H₄SiO₄, pH, EC, TDS. It was identified that the higher concentration of Uranium (156 ppb) were noted in the northern part of the study area. They are chiefly restricted to the Granitic terrain and nearby Charnockitic regions. The weathering process induces the release of higher U ions from the granitic terrain and the evaporated recharge water from the tank /reservoir  also induces the release of U ions from the rock matrix, it may also be due to fertilizer enriched agricultural return flows. The key source for all these processes and hydrogeochemical processes is identified to be lithology which inturn controls all the other processes in the study area.

Abstract

Dissolved Organic Carbon (DOC) consisting of water soluble organic molecules and by products of organic decomposition and chemical degradation processes, constitutes a critical link in carbon and nutrient cycles. The quality, or chemical and physical character, of DOC affects the degree to which it is transformed by biological and chemical processes. The significance of DOC was studied in layered coastal aquifers of the Pondicherry region during four different seasons. Pondicherry region has varied geological set up ranging from Cretaceous to Recent formations. A total of 52 groundwater samples were collected from various aquifers like Alluvium, Tertiary(Upper Cuddalore, Lower Cuddalore) and Cretaceous for two different seasons of pre- monsoon(PRM), and post-monsoon (POM). The samples were analyzed for major ions and DOC. The range of DOC in the study area is 0-14 mg/l. Very high DOC concentrations were measured during PRM in the samples from Alluvium and Lower Cuddalore Formation. The samples of these formations were compared with pH, Ionic strength, log pCO₂ and carbonate minerals concentration. The alluvial aquifer shows that pH governed dissolution along the coastal tracts and in Upper Cuddalore formation it’s based on interaction between aquifer matrix and groundwater.

Abstract

The development and management of fresh groundwater resources in coastal aquifers are seriously constrained by the impact of seawater intrusion. The coastal aquifers are fragile and this situation becomes more intense like that of the coastal Cuddalore region. The geochemical signature of groundwater of Cuddalore coast was studied for Pre Monsoon, Southwest, North east and Post Monsoon seasons by collecting total of 64 groundwater samples in each season. The collected samples from were analysed for physical parameters, such as electrical conductivity (EC), pH and major ion concentrations, such as Ca, Mg, Na, K, Cl, HCO₃, PO₄ and SO₄. Interpretation of analytical data shows the predominance of  Na–Cl type   in PRM and Ca- Mg-Cl type  is the dominant facies during POM. The Chaddas evaluation diagram shows that the hydrogeochemical evaluation plot for PRM samples fall in  Na-Cl type. The ratios of Na/Cl and Cl/HCO₃ is also enumerated the fact that the most of the samples from PRM and few samples from other seasons also indicates dominance of salt water intrusion.

Abstract

In Gadilam river basin, groundwater is found in both hard rock and sedimentary terrain and is the most important source of rural/urban drinking water supply. Gadilam river basin has gained its importance due to the presence of Neyveli Lignite open cast mine (NLC), group of industrial estate (SIPCOT), extensive depressurization of Cuddalore aquifer and boreholes of New Veeranam Scheme (NVS) in the downstream of the basin. A total of 178 water samples were collected in four different seasons at various lithologies. The collected samples were analyzed for various physico-chemical parameters using standard procedures. Geochemical indicators of groundwater were used to identify the chemical processes that control hydrogeochemsitry. Interpretation of hydrogeochemical data suggests that leaching of ions followed by weathering and anthropogenic impact controls the chemistry of the groundwater. Isotopic study reveals that recharge from meteoric source in sedimentary terrain and rock water interaction with significant evaporation prevails in hard rock region. This thorough understanding helps us to make judicial usage and to maintain the quality of this commodity.

Abstract

A study on colloids in groundwater and its relationship with the geochemical parameters is reasonably essential because of its facilitating nature to transport radionuclides in groundwater. Colloid sampling has been carried out in the coastal aquifers of southeast coast of India. Two different bore wells were selected based on the distance from the coast to collect groundwater samples. On the basis of the result achieved from this study, a reliable representation is emerging. The values of pH and EC are governed by the different size fraction of colloids. In this study, the relation between different size fractions of groundwater colloids and its pH, TDS and EC were carried out. These parameters were analyzed in the lab and its influence with four fractions of colloid like 1.2, 0.8, 0.45 and 0.22 µm have been discovered by smooth scatter plot. The accumulation of particles weighting by normal weighing instrument. There is an higher accumulation of particles found in Kalpakkam than Anupuram in all the size fractions. For separation of particles high frequency pressure was used by ultrasonic cleaner had been carried out. This method is very simple and more reasonable than any other methods.