Parasitic phanerogams are extremely interesting group of dicotyledonous species which attract the man since the time immemorial. Mistletoes (members of Loranthaceae and Viscaceae) are the dominant group of angiospermic shoot or stem hemiparasites which are found to grow on the branches of host shrubs and trees, absorb water and organic solutes directly from the host vasculature. These are notorious parasites capable of destroying the economically important plants. It can also cause serious threat to silviculture and horticultural crops [1].

Many studies have already indicated that the host parasite relationship of other species of Dendrophthoe [2]. Most of the fruit and timber yielding trees are seriously damaged with mistletoes [3]. The effects of mistletoes on their hosts can include decreased growth and vigor, poor fruit set or yield, malformed woody tissues, sparse foliage, top withering, susceptibility to insect and other disease attacks and early death [1]. The list of hosts that have been attacked by other species of Dendrophthoe are enlisted, while Dendrophthoe gamblei is seriously lacking. The present study reports the range of the host plants for D. gamblei from southern districts of Karnataka.

The study area [Fig. 1] is located between 76º. 25´. 00´´E to 78º. 15´. 00´´E longitude and 14º. 30´. 00´´N to 11º. 30´. 00´´N latitude. It comprises 5 districts which are bordered by Andhra Pradesh and Tamil Nadu states and covers mainly Tumkur, Chikkaballapura, Bangaluru (Rural), Ramanagara and Chamarajanagara Districts. Sampling areas includes the forests of Revanasiddeswara Betta of Ramanagara taluk and district, Siddara Betta of Tumkur district's Koratagere taluk, Barachukki falls forest of Chamarajanagara district's Kollegal taluk, Road sides along Hyderabad-Bengaluru Highway near Devanahalli taluk of Bengaluru rural district and Kanive road of Chikkaballapura taluk and district. 

To Study and document the diversity of new hosts of D. gamblei from different geographical regions of South Karnataka. 

Frequent field trips were undertaken to different geographical regions of Southern Karnataka. The current study was carried out during 2018 and 2023 to gather plant specimens from the Loranthaceae family. The collected host specimens were brought to the laboratory and identified with the help of Flora of the Presidency of Madras [4], Flora of the Presidency of Bombay [5] and Flora of Karnataka Vol-II [6]. For collection and preservation of plants, the methods outlined by [7] were followed.

D. gamblei shows a wide range of hosts and occurs on shrubs as well as woody tree species including wild and cultivated taxa. Almost 7 species of the host belong to the subfamily Caesalpinioideae of the family Fabaceae, three species in Rutaceae, two species in Rhamnaceae and remaining 7 hosts distributed one each in Meliaceae, Muntingiaceae, Boraginaceae, Malvaceae, Sapotaceae, Lythraceae and Apocynaceae [Table. 1].

A total of 19 species belongs to 19 genera and 10 different families were recorded as new hosts of D. gamblei for the first time India [Fig. 2][Fig. 3][Fig. 4]. All the host plants were identified up to the species rank. The number of host species recorded ranged from 1 to 7. All the recorded host species were dicotyledonous angiosperms without even a single taxa from monocotyledons and none were herbaceous.

The current catalogue of the host species D. gamblei in southern geographical regions of Karnataka indicated a great diversity of plant species which can be parasitized. It would appear that no shrub or tree is immune to this parasite attack under right conditions. In addition it is very important to distinguish the terms like host range, host preference and host specificity.

Host range refers to the total number of plant species that can be parasitized. If the parasite appears on only one group of hosts and not others, such conditions may be considered as host preference. Based on limited number of host species, it can be called as host specific. 

These understanding of the interaction between parasitic angiosperms and their host species lags behind that of these plant symbiotic association [8]. Two host species such as Albizia amara (Roxb) Boivin and Strychnos colubrina L. [9]. As of now 21 species are recorded as hosts to D. gamblei including 19 new hosts recorded during the present investigation.

Until now the knowledge of host species for D. gamblei has not been documented. The current study establishes a baseline for the study of host mistletoe combination in Karnataka. There is no host specificity for D. gamblei hence during the present investigation a total of 19 host species of dicotyledonous angiosperms were recorded as new hosts for the first time in India.

The first author is thankful to Bangalore University for providing financial assistance in the form of Research fellowship and Department of Botany, BUB for providing facilities.