Abstract: Background: The cotton mealybug Phenacoccus solenopsis (Tinsley, 1898), (Hemiptera: Pseudococcidae) was an important plant pest, causing major economic, environmental and social impact. It is a polyphagous pest and multiplies on different hosts like field crops, horticultural, fruit, vegetable and ornamental plants. Materials and Methods: A reconnaissance field survey was conducted during the two successive years February, 2014 till February, 2016 in Alexandria and Behaira governorates. Samples were collected from urban and rural areas including planting and implanting host plants. Results: Six different localities were investigated in Alexandria and Behaira governorates. In Alexandria the recorded host plants were more diverse including ornamental, vegetables and herbal host plants. Vegetable crops were predominantly cultivated in the investigated area sites of Behaira governorates. Conclusion: Obtained result recorded a total of 22 species of host plants belonging to 12 families, among them are: Malvaceae, Tiliaceae, Portulaceae, Solanaceae and others. Eight species of herbal host plants were recorded as a new record in Egypt for the first time.
INTRODUCTION
In a relatively short period time, potentially invasive Phenacoccus solenopsis (Tinsley, 1898), (Hemiptera: Pseudococcidae) has been reported occurring in several countries causing severe losses of economically important crops. The cotton mealybug is a polyphagous pest recorded over wide range of plant families all over the world EPPO1. It has a wide geographical distribution2 observed it from approximately 37 various localities from different ecological zones around the world. Hodgson et al.3 illustrated the immature stages as well as the adult female and male.
The first record of P. solenopsis damaging a crop was made by Fuchs et al.4 who reported it on cultivated cotton in Texas, USA. Other crops have been damaged in Chile, on Solanum muricatum (Ait.) By Larrain5 and in Brazil on Solanum lycopersicum L., Solanaceae by Culik and Gullan6. De Willink7 recorded it from Argentina on false ragweed, Ambrosia tenuifolia Spreng. (Asteraceae). It was first found in Asia (Pakistan) in 20058,9 and soon afterwards10 recorded it from India. Hodgson et al.3 recorded it from Thailand and Taiwan in (2006). Cotton (Gossypium hirsutum L., Malvaceae) is one of its most favored hosts, the economic impact of P. solenopsis in Asia are from Pakistan and India, there have been many damaging outbreaks, severely affecting their cotton industries11.
In Egypt, it was first recorded on unknown host plant by Abd-Rabou et al.12. Then the invasive cotton mealybug recorded on new hosts of family: Solanaceae in Qalyoubia governorate13. In Alexandria governorate, Abou-Ghoneim14 recorded it on two ornamental plants, afterwards based on information reported from field researchers in the region Southern of Behaira governorate and from Burg El-Arab and Alexandria governorate, high infestations was detected at these regions on hosts of families Malvaceae, Tiliaceae, Portulaceae , Solanaceae and more.
Keeping in view the outbreak of the cotton mealybug on cotton and other economically important host plants around the world, the proposed study was carried out to survey host plants of cotton mealybug P. solenopsis in surrounding areas. This study will help to recognize different host plants of cotton mealybug for researchers, extension workers, farming community and all the stakeholders related to cotton crop and other field crops.
MATERIALS AND METHODS
Study area: Several field surveys were carried out of the two governorates Alexandria, Behaira and North coast from February, 2014-2016. The entire area were located between latitude: 31°12'56" Nand longitude: 29°57'18" E. The areas of the studied farms ranged between 0.52 and 1.56 acres. Samples of vegetables crop and ornamental plants were collected from urban and rural localities. The samples including planting and implanting host plants.
Examined plants are identified in Herbarium Unit of Agriculture Museum (Herbarium CAIM) at Giza by specialists.
Sample collection: Samples were picked up at monthly intervals throughout the period of study. Samples sizes were 10 cm2 from branches. The samples collected at random from shrubs. All alive mealybugs found on twigs, leaves, branches, stems and roots were assorted and recorded. The plant samples kept in polythene bags. The mealybugs were kept in alcohol (70%). Specimens were slide-mounted for identification using the method outlined in Williams and Granara de Willink15. Identification of the genus was carried out using the key of the Pseudococcidae family (Hemiptera: Coccoidea) according to Mckenzie16.
A literature study of host plants species of Phenacoccus solenopsis was performed on the scale net website, “www.sel.barc.usda.gov/SCALENET/scalenet.htm, Last Time Access on this Date, June 07, 2016”, used to determine historical records of the pest. In addition, a cross search at Cabi website cabi.org/isc/datasheet/109097 and EPPO websites1 in order to determine the proper information about the pest’s host plants species. Due to technical problems in the field, pictures are insufficient.
RESULTS AND DISCUSSION
The present study surveyed the host plants of the cotton mealybug Phenacoccus solenopsis (Tinsley 1898), (Hemiptera: Pseudococcidae) at Alexandria and Behaira governorates during the two successive years February, 2014-2016. Field work was carried out including 5 localities at Alexandria, Asafra, Amriya, Burg El-Arab, Nahda and North coast. At Behaira governorate field work done at Abu Homos. The study revealed the infestation including diversity of vegetable crops ornamental plants and many kinds of herbal plants (wild shrubs and weeds of arable lands). A total of 22 host plants in 18 families were reported. The following species are; Trianthemaportula castrum of family: Aizoaceae, Amaranthus lividus and Amaranthus of family: Amaranthaceae, Nerium oleander of family: Apocynaceae, Helianthus annus, Xanthium spinosum and Xanthium strumarium of family: Asteraceae, Atriplex lindleyi, Atriplex sp. and Chenopodium sp. of family: Chenopodiaceae, Convolvulus althaeoides of family: Convulvulaceae, Medicago laciniata of family: Fabaceae, Alcea rosea and Hibiscus rosa-sisensis of family: Malvaceae, Anagallis sp. of family: Primulaceae, Lycopersicon lycopersicum, Abelmoschus esculentus and Nicotiana glacua of family: Solanaceae and Lantana camara of family: Verbenaceae. The species within each family are listed alphabetically from Alexandria district.
The following species from Abu Homos site Behaira Governorate Corchoru solitorius and Hibiscus rosa-sisensis of family: Malvaceae, Portulaca oleracea of family: Portulacaceae and Abelmoschus esculentus, Lycopersicon esculentus and Solanum melongena of family: Solanaceae The species within each family are listed alphabetically.
The previous results of this study have been summarized in two table. Table 1 shows the list of host plant species in alphabetical order at Alexandria governorate in order of their vicinity and their type ranking. Table 2 gave the similarity at Behaira governorate.
Table 1 included 20 host plant species belonging to 11 families found in different localities throughout Alexandria governorate arranged alphabetically. Eighteen host plants of them were recorded in this study during the survey. Three of them Codiaeum variegatum and Nerium oleander, host plants species were recorded from literature14 and the third host plant Artemisia annua which recorded from3,17. Its medicinal benefits was reported by El-Askary et al.18 and Hodgson et al.3.
Vegetable crops: Six vegetable crops were predominantly cultivated in the investigated area sites. These include, Abelmoschus esculentus (Okra lady’s finger), Corchorus olitorius L. (Mulukhiyah), Lycopersicum esculentum (Tomato), Solanum melongena L. (Egg-plant) and Portulaca oleracea L. (Regla common purslane) from families: Malvaceae, Solanaceae and Portulacaceae, respectively.
Also, Ibrahim et al.13 recording P. solenopsis infesting members of family Solanaceae, egg-plant (Solanum melongena), tomato (Lycopersicon esculentum) in Qalubia and Dakahliya governorates.
Vegetable crops of these families were of economic important in our local and international markets. The infestation was detected in the cultivated okra crop (Abelmoschus escsulentus), decreasing the quality of the yield product in the market.
| Table 1: | Localities and host plants of the mealybug Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) in Alexandria governorate, Egypt during 2014-2016 |
| Dot represents the literature study | |
| Table 2: | Localities and host plants of the mealybug Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) in Behaira governorate, Egypt during 2014-2016 |
According to the last estimates from the Egyptian Ministry of Agriculture and Land Reclamation in Behaira the total cultivated area of okra was 398.94 acres with average of 52.92% yielding 1122 t. In Alexandria the cultivated area about 35.29 acres only in private sectors in new reclaimed areas at El-Nahda district.
Ornamental plants: Five localities from the visited regions have the major numbers of infested host plants during the survey Table 1 and 2. In Alexandria the mealybug Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) was recorded from Asafra, Faculty of Nursery, Amriya, Burg El-Arab, Nahda and North coast. Hibiscus rosa-sisensis was only recorded from many sites of investigation and also from Behaira governorate. Phenacoccus solenopsis was found causing serious damage to a collection of succulent plants Hibiscus, Lantana, sunflower and hollyhock at private botanical gardens. These results represented in Table 1 and 2. These findings are in agreement with Arif et al.19 and Ben-Dov20. Abdul-Rassoul et al.21 recorded it infested Hibiscus-rosa sisensis for the first time in Iraq during August, 2014 to July, 2015.
Other incidental host plants of ornamental plants were as fellow, Amaranthus lividus, Codiaeum variegatum, Xanthium spinosus and X. stramarium were found in many localities infested by P. solanopsis which agreed with Abbas et al.8. High infestation was found on the ornamental plant hollyhocks Alcea rosa Malvaceae implanted in private garden in Alamriya district (Fig. 1). The species Nerium oleander collected from Faculty of Nursery with the Hibiscus rosa-sisensis only written from literature study14.
Wang et al.22 suggested that high summer temperature and excessive moisture in autumn were likely to restrict population growth, indicating that areas with extremely high rainfall were unfavorable for serious infestation by the pest. According to Wang et al.22 the weather conditions in Egypt makes the environment not suitable for proliferation of P. solenopsis as it is mainly a tropical species.
Some ornamental and herbicial plants at Amriya district were helpful in spreading the infestation widely by humans, either deliberately as an ornamental flower or accidentally and were documented as a new locality for host plants.
Herbal plants: A total of ten host plants species were surveyed from Alexandria governorate during the present study. The recorded eight infested herbal species are: Trianthemaportula castrum family: Aizoaceae, Amaranthus sp. family: Amaranthaceae, Chenopodium sp. family: Chenopodiaceae and Convolvulus althaeoides family: Convulvulaceae, they are all considering as weeds of arable lands. The mealybugs are well concealed in protected places as under the succulent leaves, near the stem or the crown and low infestations are easily overlooked.
| Fig. 1(a-d): | (a-b) Infestation of adult and premature ages on leaves, stem and branches of Alcea rosea and (c-d) Magnified photo of the nymph and adults of Phenacoccus solenopsis |
The mealybugs crawl actively from site to another and can spread rapidly when favorable conditions, using their own legs or they may hitch a ride on an air current and travel effortlessly over much greater distances. Sticky honeydew is excreted on infested plants, when population levels are high11,23.
In Table 1, the pest recorded infested Nicotiana glacua R.C. Graham, wild tobacco shrub family: Solanaceae at Burg El-Arab district in Alexandria24,11. The host plants species of Anagallis sp., Atriplex lindleyi and Atriplex sp. of families Primulaceae and Chenopodiaceae respectively found to be infested with P. solenopsis. This is the first record for the previous eight host plants species at Alexandria governorate and in Egypt. This finding is in full agreement with the report of Abbas et al.8.
Phenacoccus solenopsis has become an aggressively invasive species on agriculture and ornamental plants and has spread rapidly between countries. This may be due to its plasticity in its morphology and ability to live under a wide variety of environmental conditions3.
CONCLUSION
The present study demonstrates that site Alexandria much diverse than site Behaira. Alexandria shows highest diversity of herbal and ornamental host plants with eight host plants for each, due to expansion of urban areas. While at Behaira the vegetable crops represents the dominant host plants with five species. The total host plants of investigated species of all sites represented by 22 host plants from 12 families. Three of them are from literature. The study recorded two vegetable crops and eight ornamental plants in Alexandria governorate and six host plants at Behaira for the first time. This study also recorded eight species of herbal host plants as new record in Egypt.
SIGNIFICANCE STATEMENTS
| • | The present study surveyed Phenacoccus solenopsis at Alexandria and Behaira governorates. A total of 22 host plants of 12 families were recorded |
| • | In Alexandria governorate 2 vegetable crops and 8 ornamental plants were recorded |
| • | Six host plants of vegetable crops were demonstrated at Behaira governorate |
| • | This study revealed new record for the first time of 8 species of herbal host plants in Egypt |
| • | This will encourage stakeholders to put a limit to its movement from one place to another by implementing more laws and legislations |
ACKNOWLEDGMENT
The authors want to express their great thanks to Professor Hamdy Emara, Professor at Agriculture Research Center (ARC) for providing material specimens from Abu Homos locality. Also deep thanks to the botanist Professor Sherif Shokry Elkhanagry Flora and Phytotaxonomy Research (Herbarium CAIM) for authoritative identification of the host plant samples.