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1 Journal home page: INTERNATIONAL JOURNAL OF INNOVATIVE AND APPLIED RESEARCH RESEARCH ARTICLE Impact of physiochemical characteristics of sunflower leaves on insect pests population Abdul Ghani Lanjar, Hakim Ali Sahito *, Abdul Waheed Solangi and Sajjad Ali Khuhro Department of Entomology, Sindh Agriculture University, Tandojam Sindh, Pakistan. Abstract: In order to monitor the population buildup of various insect pests of sunflower (whitefly, aphid, jassid and H. armigera) to compute the correlation between plant physiochemical characteristics and insect pest population, the study was carried out. The results revealed that whitefly overall mean population was observed (2.84±0.26); while jassid (2.98±0.76), aphid (0.30±0.05) / leaf and H. armigera (av. 0.35±0.07) /plant. The plant physicochemical characteristics improved with growth and development of plant with the exception of leaf Nitrogen (N) content that decreased in the leaf sap with increasing plant age. Correlation studies showed strong positive correlation (r=0.7402**) between whitefly population and leaf Nitrogen (N) content, suggested that with increasing leaf Nitrogen (N) content, the whitefly population increased significantly (P=0.059). Negative correlation between whitefly population and plant height (r= *), trichomes (r= **), ph (r= NS ), EC (r= **) and OP (r= **) suggesting negative impact of improving plant physicochemical characteristics on whitefly population. Strong positive correlation of jassid population with plant height (r=0.8801**) suggested that improvement in plant height will result increase in jassid population significantly (P<0.05). There was a strong negative correlation of leaf N content (r= **), indicated that increasing leaf Nitrogen (N) will result negative impact on jassid population. Strong positive correlation of H. armigera population with plant height (r=0.6705**), trichomes (r=0.5909*) and leaf Nitrogen (N) content (r=0.7017**) was noted suggesting that with increasing plant height, trichomes and leaf Nitrogen (N) content, the H. armigera population will increase significantly (P<0.05) increasing ph, EC and OP would result a minor increase in H. armigera population. Key Words: Sucking, chewing insects, phsiochemicals, Helianthus. 1. Introduction Sunflower, Helianthus annuus (L.) belongs to the family Asteraceae is one of the most important oil crops globally and is grown on over 22 million hectares worldwide, with a production of 26 million tones (Skoric et al., 2007). It is cultivated for edible seed (Khan et al., 2007). It was introduced in Pakistan during 1960 with the object of bridging the gap between production and consumption of edible oil in the country (Burney et al., 1990). The balance of 72% is met through imports; the imported edible oil s budget is growing into billion of dollars becoming a big drain on our foreign exchange reserves. Edible oil and oilseeds import cost of US$ was more than 2000 million during The edible oil requirement stood at million tones in the same year. This included million tones from imported sources (oil and oilseeds). Local production remained at million tones. Demand of edible oil increased at a rate of 5.4% annually. At this rate, our annual requirement would be million tones after five years and if local production is not increased rapidly annual import bill will raise to billion US$ (Anonymous, 2011). Insects are our rivals, because they are herbivore and ravaging our crops and are major threat to crop production. Some of them serve as vector for virus and other diseases. Leaf curling, chlorosis and premature senescence of plants can be due to severe infestation on sunflower by diseases, insects and nematodes that results a wide range of loss in production and yield of sunflower crop (Mukhtar, 2009). Sattar et al., (1984) reported the insect pests of sunflower as whitefly, Bemisia tabaci; aphids, Aphis gossypii; jassids, Amrasca devastans; bud moth, Heliothis armigera and surface grass hopper, Chrotogonus spp. Kakakhel et al., (2000) reported the insect pests attack on sunflower are Bemisia tabaci, Empoasca spp., Thysanoplusia orichalce, Diacretia obliqua, Nezara viridula, Helicoverpa armigera and Nysius inconspicuus. Aslam et al., (2000) widen the list of the pests ravaging this crop include Cutworms (Agrotis spp.), Green stink bug (Nezara viridulannaeus), American bollworm (Helicoverpa (Heliothis) armigera), Cotton aphid (Aphis gossypii Glov.), Potato aphid (lacrosiphum euphorbiae Thos.), and 115

2 Cabbage semi-looper (Plusia orichalcea Fabricius). Beside that others include sunflower caterpillar (Perigea capensis G.), Head caterpillar (Tathmopoda theoris Mayr.), Melonfly (Dacus Cucurbitae Coq.), whitefly (Bemisia tabaci Genadius), yellow flower thrips (Ankliniella sulphurea S.), several species of army worms, grasshoppers and termites, Brown bruchid (Caryedon gonaga bricius), Sawtoothed beetle (Oryzaephilus spp.) on sunflower crop and drastically effect its yield. Ashfaq and Aslam, (2001) endorsed the occurrence of Agrotis spp. (Cut worm), Odontotermes obesusi (White ants), Agapanthia dahlii (Stem borer), and Melanagromyza spp. (Stem girdler), Aphis gossypii (Cotton aphid). Others include Agnus convolvoli (Horn worm), Empoasca spp. (Jassid), Suleima helianthana (Sunflower bud moth), Helicoverpa spp. (boll worm) Spodoptera litura (Tobacco caterpillar), Plusia ohchalcea (Cabbage semilooper), also included are Homoeosoma electellum (Sunflower moth), (Green stink bug), Diacrisia obliquata (Hairy caterpillar), Myllocerus b/andus (Green weevii), ygogramma exclamationis (Sunflower beetle) and Smicronyx spp, (Sunflower seed weevil). Plant leaf chemical composition affects feeding insect body as a result the insect chemistry is highly influenced consequently activities of herbivore insects. Abdullah et al., (2006) reported that the total free amino acids brought significant changes in total phenols and ph value of treated plants and did not reduced the sugar level of plant leaves. This may be one of the causes of resurgence of B. tabaci on plants. Similarly, aphids derive their nitrogen requirement from the phloem amino acids (Douglas, 2003). Eigenbrode and Pimentel, (1988) mentioned that flea beetle densities were significantly higher on plants having added nitrogen whereas cabbage worm and diamondback moth densities significantly higher on untreated plants. Altieri and Nicholls, (2003) reported that the 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. Ramesh et al., (2005) concluded that organic crops have been shown to be more tolerant as well as resistant to insect attacks and organic rice is reported to have thicker cell wall and lower levels of free amino acid than conventional rice. Magdoff et al., (2000) indicated farming practices that cause nutrition imbalances can be lower pest resistance. Plants suffering from mineral nutrient deficiency have lower tolerance to pathogens and pests (Huber, 1980, and 1989). Chemical composition of leaf physical structure is also important for the abundance and activities of herbivore insects. (Ananthakrishnan et al., 1992) mentioned that variation in number of amino acids and their concentrations changed the response of insect pest to the crop plants as significantly higher concentration of glutamic acid develops the resistance in oats and barley against aphid, Rhopalosiphum padi (L). Trichomes are single or multicellular outgrowths of the plant epidermis and collectively constitute the pubescence / hairiness of the plant surface. These epidermal hairs in many plant species are specialized for defense against attack by insects and mites. The mode of defense used by trichomes is determined by nonsecretory or glandular, as well as their density, length, shape, and degree of erectness. When present on the plant surface at high densities, nonsecretory trichomes create a physical barrier to insect feeding on the underlying surface or internal tissues (Juniper et al., 1986). The present studies are steps forward to ascertain the causes of behavior to the plants. The results out of the studies will be utilized far IPM modules in future. 2. Materials and Methods The experiment on impact of physiochemical characteristics of sunflower leaves on insect pests population was conducted in the experimental field, of Oil Seed Section, Agriculture Research Institute Tandojam. The HO-1 variety was cultivated for this purpose on an area of ½ acre on 6 th October The plant to plant and row to row distance was maintained 8-9 and 30 inches, respectively. All agronomical practices were carried out accordingly. However, no pesticide was used thought out cropping season. Data of the insect pests population on sunflower crop were recorded on weekly basis, 50 plants were selected randomly from the experimental plot, 10 leaves per size and age i-e., young leaves partially mature leaves and fully mature leaves. Three leaves of various ages from each plant were examined for the population of whitefly, jassid, aphid and thrips, while whole plant was examined for the population of chewing insect pests. The observations on the population density of insect pests were recorded after fifteen days of sowing till the harvesting. Similarly, the same plants were examined for number of nodes per plant, leaves per plant and height of plants. Various size leaves of sunflower crop were plucked from the experimental field and brought in the laboratory of department of Entomology to ascertain the physical characteristics such as leaf size, trichome size and trichome density within the leaf sheath at weekly intervals under microscope. After determination of the physical characteristics, the plucked leaves were then soughted out. Some were kept to be dried out for N level 116

3 determination, while other leaves were grinned with the help of grinder and paste of the ground leaves was then squeezed in muslin cloth to obtained liquid juice of the leaves. The juice was then taken to the laboratory of Department of Soil Sciences, Sindh Agriculture University - Tandojam for the determination of ph levels Electrical conductivity (EC) and osmotic pressure (OP). For Nitrogen determination the leaves of sunflower were plucked weekly kept separately in paper envelopes to be completely dried up. Dried leaves were brought in the laboratory of soil science division, NIA, Tandojam where they were cleaned and each sample was kept in the oven for further removal of mixture. After drying these leaves were ground in grinder and fine power was obtained that was used for the determination nitrogen level of the leaves of sunflower at different phonological stages. The metrological record was also recorded during research work. The temperature remain during the research work was 25-32ºC and relative humidity was 50-60%. The data thus collected were subjected to analysis for variance. While, to compare the mean values was applied. For these analyses a Microsoft Excel package was used for obtained the significant results. 3. Results The data in relation to population dynamics of insect pests and physicochemical traits are presented in Tables 1 and 2, while correlations of insect pest population with physicochemical characteristics of sunflower are shown in Tables 3 to 6, respectively Whitefly, Bemisa tabacci (Gennadius) The whitefly population on sunflower was monitored from 21 st September to 7 th December 2012 and initially the insect population was 3.07 /leaf which showed an increasing trend during following two weeks reaching at peak 4.61 /leaf on 5 th October and declined sharply to 1.92 /leaf when monitored on 12 th October. The population of whitefly was 3.30 on 19 th October and later decreased slightly and sustained its population up to the last observation (2.07 /leaf). However, the whitefly population during this 12 weeks study ranged between 1.91 to 4.61 /leaf averaging 2.84±0.26 /leaf. The data (Table-1) indicated that after 5 th October, the whitefly population remained almost maintained throughout the season without considerable variation Jassid, Amrasca biguttula biguttula (Ishida) The jassid population on sunflower was maintained from 21 st September to 7 th December and at first observation the insect population was 0.46 /leaf which showed an increasing trend during coming two weeks and decreased. There was a gradual increase in the jassid population up to the 2 nd November (1.50 /leaf) and later shoot-up alarmingly (5.38 /leaf) on 9 th November and reached its peak (7.53 /leaf) on 7 th December observation. The jassid population during three months study period ranged between 0.38 to 7.53 /leaf averaging 2.98±0.76 /leaf. The data indicated that from 21 st September to 2 nd November, the jassid population was negligible, but from 9 th November onwards, the jassid population sustained and remained present in the field up to the last observation. The trend of jassid infestation on sunflower was quite different when compared with whitefly infestation. Whitefly showed high infestation during in the initial three weeks, while the jassid population shoot-up during last six weeks of the crop (Table-1) Aphid, Aphis gossypi (Glover) The aphid population was recorded in sunflower for a period of 12 weeks (21 st September to 7 th December) at the start on 21 st September the aphid population was 0.15 /leaf which increased to its peak population (0.76 /leaf) when monitored on 28 th September and later decreased gradually. The aphid population during the study period ranged between 0.15 to 0.76 /leaf averaging 0.30±0.05 /leaf. With the exception of 28 th September observation, a minor population of aphid remained in the field, but sustained its presence throughout the growing season of sunflower (Table-1) Fruit borer, Helicoverpa armigera (Hubner) H. armigera population on sunflower was monitored (21 st September to 7 th December) and initially the H. armigera population was 0.07 /plant which sustained up to 12 th October and then started increasing and reached its peak (

4 /plant) on 26 th October and then declined sharply (0.23 /plant). The H. armigera population during the study period ranged between 0.07 to 0.84 /plant averaging 0.35±0.07 /plant. After 2 nd November, the H. armigera population again increased and sustained its population up to the harvest of the crop (Table- 1). Table-1. Weekly population buildup per plant of various insect pests on autumn sown sunflower (from 21 st September to 7 th December) Obs. Date Whitefly Jassid Aphid H. Armigera Mean 2.84.± ± ± ± Physicochemical characteristics of sunflower The number of nodes was recorded at weekly interval in the experimental field of sunflower and the data (Table- 2) showed that the number of internodes increased with the development of the growth period and was in the range of 2.83 /plant to /plant averaging 9.73 nodes /plant. At the first observation on 21 st September the number of nodes was 2.83 /plant which increased to /plant at the end of experiment on 7 th December. Number of leaves of sunflower was in the range of 5.83 /plant to /plant and the number of leaves was generally associated with the progression of the growth period. At the first observation on 21 st September the number of leaves were 5.83 /plant which increased to /plant at the end of experiment on 7 th December averaging leaves /plant. Plant height of sunflower was in the range of to 177 cm and the plant height increased with the development of growth period. At the first observation on 21 st September the plant height was and at the harvest of the crop, the plant height reached to 177 cm averaging cm. In case of Trichomes, this trait was improved with the development of growth period and initially the number of trichomes was /plant which decreased in the following two weeks and highest number of trichomes (22.30 /plant) was recorded when crop was measured on 12 th October. The leaf ph was also determined from extracted sap from the sunflower leaves and the data (Table- 2) indicated that there was no linear trend as regards the observation dates are concerned, but the ph was in the range of 6.1 to 7.90 averaging However, the ph in leaf sap was higher in October and second fortnight of November. Similarly, the EC was also determined for leaf sap in sunflower and it was observed that EC of leaf sap increased with the development of plant age and physical height. However, the highest EC (23.5 dsm -1 ) was determined on 12 th October, while the lowest EC (12.1 dsm -1 ) was 118

5 determined on 19 th October. On average, the EC in the leaf sap during three months study period was observed dsm -1 during the study period. The data further showed that OP was associated with the EC in leaf sap of sunflower and highest OP (8.46) was observed on 12 th October observation and the lowest (4.35) during 19 th October observation, averaging The data in case of leaf N indicated that the leaf in sunflower was higher in September, followed by October and the lower during November onwards. The highest leaf N (4.50%) equally was determined on 28 th September and 5 th October observations while, the lowest leaf N (2.41%) equally was determined during 30 th November and 7 th December observation. However, the average leaf N content in sunflower was 3.32%. Table-2. Weekly observations on physicochemical characters of autumn sown sunflower (from 21 st September to 7 th December) Obs. Date Nodes plant -1 Leaves plant -1 Plant height (cm) Trichomes leaf -1 Leaf ph Leaf EC dsm -1 OP Leaf (%) N Mean 9.73 ± ± 6.93 ± ± 5.46 ± 3.32 ± ± ± Correlation coefficient (r) of whitefly population vs Plant physicochemical characteristics There was a strong positive correlation (r=0.7402**) between whitefly population and leaf N content, which suggested that with increasing leaf N content in sunflower, the whitefly population will increase significantly (P=0.005). However, the negative correlation between whitefly population and number of nodes (r= *), leaves (r= NS ), plant height (r= *), trichomes (r= **), ph (r= NS ), EC (r= **) and OP (r= **) suggested that with increasing these physicochemical characteristics, the whitefly population will be decreased. There was a highly significant (P=0.001) correlation of trichomes with whitefly population suggesting that increasing trichomes on sunflower leaves will result in suppression of whitefly population (Table- 3). Table-3. Correlation coefficient (r) of whitefly population and physicochemical characteristics of sunflower Physicochemical characteristics Correlation (r) P-Value Significance Nodes plant * Leaves plant NS Plant height (cm) * Trichomes leaf ** 119

6 Leaf Ph NS Leaf EC (dsm -1 ) ** OP ** Leaf N (%) ** 3.7. Jassid population vs Plant physiochemical characteristics There was a strong positive correlation of jassid population with number of nodes (r=0.7817**), leaves (r=0.6136*) and plant height (r=0.8801**), which suggested that with increasing number of nodes, number of leaves and plant height, the jassid population will also increase significantly (P<0.05). However, there was a strong negative correlation of leaf N content (r= **) with jassid population, suggesting that increasing leaf N will result in decreased jassid population. The correlation between jassid population and number of trichomes, ph, EC and OP was positive but non-significant (P>0.05). This indicates that with increasing value of trichomes, ph, EC and OP, the jassid population will increase negligibly (Table- 4). Table-4. Correlation coefficient (r) of Jassid population and physicochemical characteristics of sunflower Physicochemical characteristics Correlation (r) P-Value Significance Nodes plant ** Leaves plant * Plant height (cm) ** Trichomes leaf NS Leaf ph NS Leaf EC (dsm -1 ) NS OP NS Leaf N (%) ** 3.8. Aphid population vs Plant physicochemical characteristics The correlation coefficient (Table- 5) indicated that there was negative and non-significant (P>0.05) correlation of aphid population and all the plant physicochemical characteristics with the exception of leaf N content which indicates a positive but non-significant (P>0.05) correlation with aphid population. This suggested that with increasing values for plant physicochemical characteristics, the aphid population will slightly be depressed, while with increasing leaf N content, the aphid population was expected to increase slightly. Table-5. Correlation coefficient (r) of Aphid population and physicochemical characteristics of sunflower Physicochemical characteristics Correlation (r) P-Value Significance Nodes plant NS Leaves plant NS Plant height (cm) NS Trichomes leaf NS Leaf ph NS Leaf EC (dsm -1 ) NS OP NS Leaf N (%) NS 3.9. H. armigera population vs Plant physicochemical characteristics There was a strong positive correlation of H. armigera population with number of nodes (r=0.7164**), leaves (r=0.6283*), plant height (r=0.6705**), Trichomes (r=0.5909*) and leaf N content (r=0.7017**) which suggested that with increasing number of nodes, number of leaves, plant height, trichomes and leaf N content, the H. armigera population will increase significantly (P<0.05); while positive and non-significant (P>0.05) correlation of H. armigera population with ph, EC and OP was determined, indicating that with increasing values of these traits, the H. armigera population will increase negligibly (Table- 6). 120

7 Table-6. Correlation coefficient (r) of H. armigera population and physicochemical characteristics of sunflower Physicochemical characteristics Correlation (r) P-Value Significance Nodes plant ** Leaves plant * Plant height (cm) ** Trichomes leaf * Leaf ph NS Leaf EC (dsm -1 ) NS OP NS Leaf N (%) ** 4. Discussion The findings of the present study indicated that whitefly population reached its peak (4.61 /leaf) on 5 th October (av. 2.84±0.26 /leaf); peak jassid population (7.53 /leaf) noted on 7 th Dec. (av.2.98±0.76 /leaf); peak aphid population (0.76 /leaf) found on 28 th Sep. (av. 0.30±0.05 /leaf) and peak H. armigera population (0.84 /plant) noted on 26 th Oct. (av. 0.35±0.07 /plant). The insects are herbivore, ravaging the crops and a threat to agricultural productivity. Sunflower is also attacked by numerous insect pest species and in result the crop production is far below the potential yields. Whitefly, jassid, aphid and H. armigera are considered as the devastating insect pests for sunflower (Skoric et al., 2007). The plant physicochemical characteristics improved with the growth and development of plant with the exception of leaf N content that decreased in the leaf sap with increasing plant age. Correlation studies showed strong positive correlation between whitefly population and leaf N content, suggested that with increasing leaf N content, the whitefly population will increase significantly. Negative correlation between whitefly population and nodes, leaves, plant height, trichomes, ph, EC and OP suggesting negative impact of improving plant physicochemical characteristics on whitefly population. Strong positive correlation of jassid population with nodes leaves and plant height suggested that improvement in these traits will result increase in jassid population significantly. There was a strong negative correlation of leaf N content, indicated that increasing leaf N will result negative impact on jassid population. Strong positive correlation of H. armigera population with nodes, leaves, plant height, trichomes and leaf N content was noted suggesting that with increasing nodes, leaves, plant height, trichomes and leaf N content, the H. armigera population will increase significantly; increasing ph, EC and OP would result a minor increase in H. armigera population. These results are partially supported by Beattie and Marcell, (2002) who reported that plant leaf chemical composition affect feeding insect body as a result the insect chemistry is highly influenced. This quantitative knowledge of these leaf surface properties is highly relevant to the interactions of leaves with environmental factors such as microbes, insects, agricultural chemicals, and pollutants. Low N fertility did not affect whitefly, but amino acid content in leaf is markedly decreased due to whitefly infestation. Abdullah et al., (2006) reported that the total free amino acids brought significant changes in total phenols and ph value of treated plants and did not reduced the sugar level of plant leaves. Similarly aphids derive their nitrogen requirement from the phloem amino acids (Douglas, 2003). Altieri and Nicholls, (2003) reported that plant N level can affect susceptibility of plants to insect pests by altering plant tissue nutrient levels. Research showed 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. Magdoff et al., (2000) indicated farming practices that cause nutrition imbalances can lower pest resistance. Chemical composition of leaf physical structure was also important for the abundance and activities of herbivore insects (Ananthakrishnan et al., 1992). Trichomes were single or multicellular outgrowths of the plant epidermis and collectively constitute the pubescence (hairiness) of the plant surface. These epidermal hairs in many plant species were specialized for defense against attack by insects and mites (Juniper et al., 1986). Walker and Zareh, (1990) found that whitefly preferred incompletely expanded leaves over all other leaf ages their preferences to the young leaves that were completely expanded but not yet dark green. Mukhtar, (2009) reported that increasing N level in plants stimulates the insect pests infestation. According to the comparative analysis of the results of present investigation and the opinions of the past researches, it is found that plant physicochemical characteristics may influence the infestation level of the insect pests. There is a need to exploit this advantage further by studying the N levels that influences the plant physicochemical properties in favour or against the insect pest infestation. Population of all the insect species showed stability in the field throughout the growing season of sunflower. Whitefly showed high infestation during the initial three weeks, while the jassid population shoot-up during last 121

8 six weeks of the crop. With increasing nodes, leaves, plant height, trichomes and leaf N content, the H. armigera population increased significantly. Increasing ph, EC and OP resulted with a minor increase in H. armigera population. On the basis of findings of the present study, it can be recommended that the farmers should avoid the excessive use of Nitrogen and Irrigation scheduling may properly the managed, because insect pest infestation is partially associated with the Physiochemical changes in plant due to excessive use of N and irrigation water. References: Abdullah, Singh J, Sohal BS, Behavioral hormoligosis in oviposition preference of Bemisia tabaci on cotton. Pesticide Biochem. and Physio., 84: Altieri MA, Nicholls CI, Soil fertility management and insect pests: harmonizingsoil and plant health in agroecosystems. Soil & Tillage Res., 72: Ananthakrishnan ΤΝ, Gopichandran R, Gurusubramanian G, Influence of chemical profiles of host plants on the infestation diversity of Retithrips syriacus. J. Biosci., 17: Anonymous, Agricultural statistics of Pakistan. Govt. of Pakistan, Ministry of food, Agriculture live stock, economic wing, Islamabad, Pakistan. Ashfaq M, Aslam M, Resistance of different sunflower (Helianthus annuus L.) Genotypes against the attack of Aphis gossypii Glover, Nezara viridula (L.) and Thrips tabaci Lind, in Field. J. Biol. Sci., 1: Aslam M, Suleman N, Riaz A, Rehman A, Zia Q, Insect Pests found on Helianthus annuus L. (Compositae) in the Potohar Region of Pakistan. Pak. J. Biol. Sci., 3: Beattie GA, Marcell LM, Effect of alterations in cuticular wax biosynthesis on the physicochemical properties and topography of maize leaf surfaces. Plant, Cell and Environment. Blackwell Science Ltd., 25: (1 16). Burney K, Ahmad I, Aslam M, Charcoal rot and important disease of sunflower and its control. Progressive Farming. 10: Douglas AE, Nutritional physiology of aphids. Advances in Insect Physiology. 31: Eigenbrode and Pimentel, Effects of manure and chemical fertilizers on insect pest populations on collards. Agriculture, Eco. & Envi., 20: Huber DM, The role of mineral nutrition in defence, In: Plant Diseases (Eds. Harshfall, JG. and Cowling, EB.), New York, Academic Press, Pp Huber DM, The role of nutrition in the take all disease of wheat and other small grains, In: Soil borne Plant Pathogens: Management of Diseases with Macro and microelements. (ed. Engelhard, AW). The American Phytopathological Society. St. Paul, Minnesota, USA. APS Press, Pp Juniper Barrie E, Richard T, Southwood E, eds The Plant Surface and Insects. London: Edward Arnold Ltd. Kakakhel SA, Islam N, Amjad N, Malik MA, Insect pests complex of sunflower (Helianthus annuus L.). Pak. J. Biol. Sci. 3: Khan SK, Macrophomina phaseolina as causal agent for charcoal rot of sunflower. Mycopath. 5: Magdoff F, van Es H, Building soils for better crops. 2 nd ed. Sustainable Agri. Pub. Burlington, VT. 122

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