Diversity and infestation of mistletoes in cultivation of sengon (Falcataria moluccana (Miq.) Barneby&J.W.Grimes) in Malang East Java Indonesia

Mistletoes are hemiparasitic plants growing in the wild and cultivation plants such as sengon (Falcataria moluccana). Research aimed at inventing the diversity and infestation of mistletoes was conducted in cultivation areas of sengon in Malang Regency East Java Indonesia from September – December 2021. Data on mistletoes and their hosts was collected by exploratory and descriptive methods in ten districts and twenty villages. Purposive sampling was used and determined along tracks in line transects where sengon cultivation was found. Sample plots of 10x10 m were determined and made in each pattern of cultivation to enumerate the number and species of trees and mistletoes, and to measure the diameter of stems. The results showed that there were only two species of mistletoe discovered in sixteen cultivation patterns of sengon namely Scurrula atropurpurea (Blume) Danser and Viscum ovalifolium L. S. atropurpurea was the most dominant mistletoe in cultivation of sengon with parasite number of 906 individuals. The highest number of trees, infested trees, and mistletoes were obtained in the monoculture pattern of sengon. The highest severity index of mistletoe infestation was found in tangerine citrus + Sengon, i.e., 15. The average value of SI in all cultivation patterns was categorized as low, i.e., 5.28.


Introduction
Sengon (Falcataria moluccana) is one of popular timber plants cultivated widely in Indonesia, especially in Java.The wood production of sengon increased annually in Indonesia both nationally and regionally.The production of sengon by the timbers companies in Indonesia increased from 62270 m 3 in 2019 to 152014 m 3 in 2021 [1] while in Malang Regency East Java increased from 6122.45 m 3  to 17803.92 m 3 during 2013 -2015 [2].Cultivation of sengon has several advantages such as high economical value, easy to sell [3][4], fast growing tree and adaptive to various soil condition [3] and relatively easy in plant management.Khairuzani [4] reported that cultivation of sengon in District of Kemling, Bandar Lampung Province was profitable with value of Net B/C, Gross B/C, NPV, and IRR, i.e., 4.81, 4.26, IDR 97,068,99.00,and 76.99%, respectively.Cultvations of sengon were conducted monoculturally and polyculturally.Polyculture is the common cultivation of sengon by famers in Indonesia.Solikin and Danarto [7] reported that sengon was cultivated as agroforests in various cultivation patterns in Bondowoso Regency mixed with other crops or timbers such as maize (Zea mays), paddy (Oryza sativa), cassava (Manihot esculenta), and coffea (Coffea canephora).
Mistletoes absorb water and minerals by their haustorium for their life so that they will reduce their hosts growth [12].The parasitization and infestation of mistletoes caused stunted growth, mortality, and reduced yield of citruses, i.e., 65%, 55%, and 95% respectively [13].The infestation of european mistletoe, V. album caused damage and ree crown defoliation on forest trees in Central Europe [14] while mistletoe D. pentandra caused death most of distal branches and twigs of C.fistula in Purwodadi Botanic Garden [15] and other tree species.
Studying of pests' diversity, population and infestation on plants cultivation is important in pests control management to increase plants growth and yield.The Study of pests such as insects and fungus on sengon has been reported more during this time such as gall rust disease (Uromycladium falcatarium [16], Xystrocera festiva [17], Aspergillus niger [18] Eurema blanda, and Schistocerca pallens [19].However, the study of mistletoes diversity, infestation and severity on sengon has not been reported, especially in Malang Regency East Java even in Java.Studying of diversity and infestation of mistletoes on fruit plants had been reported in East Java [9]. The research aimed to know and determine diversity and infestation severity of mistletoes on several cultivation patterns of sengon (F.moluccana) in Malang Regency, East Java Province, Indonesia.The study will give information diversity and how severe the infestation of mistletoes on cultivation of sengon.

Time and location
Research was conducted in Malang Regency East Java Province in September -December 2021 at altitude about 100 -900 m asl.Malang Regency is located in East Java Province in altitude 0-3600 m asl with area about 2977.05 km 2 .The coordinates position of this regency at 112 o 17', 10.90" -112 o 57', 00.00" E and 7 o 44', 55.11' -8 o 26', 35.45" S (Figure 1).Plateau zone (Kendeng Mountains) locates in the  Data were collected by exploratory and descriptive methods using line transect along tracks of exploration.Purposive sampling was used in sengon cultivation areas along tracks of exploration.Sample plots 10x10 m were determined and made by random in each pattern of cultivations to enumerate number of trees, infested trees, and mistletoes also to measure stem diameter of sengon.The number of plots in each block observation in each cultivation pattern was 1-4 plots depended on the number of trees of sengon.Fivety-five blocks observation consisted 133 plots had been determined and made from the sampling (Table 1).Each tree in the plots was measured its diameter at 120 cm DBH, counted the number of the trees and mistletoes.Identification of trees and mistletoes species was conducted directly in fields.Herbarium specimens and photograps were used if the trees and mistletoes not to be identified in the fields.Identification and validation of plants refered to [20] and Plant of The World Online [21].The number of mistletoes in each infested trees was scored to enumerate and determine Severity Index of Parasite Infection [13] as showed in Table 2.The level of severity index (attacking intensity) of mistletoes in cultivation patterns of sengon were assessed using the formula below  and categorized following [23] (modified) in Table 3: where P=severity score, Q=number of infected plants having the same score, M=total number plants observed, and N=maximum rating scale number.Analysis of vegetation was conducted to determine tree species composition, relative density (RD), relative frequency (RF), Relative dominance (RDom) and important value index (IVI) of trees in cultivation patterns of sengon.They were calculated following [24].Spearman's correlation analysis is used to ditermine the correlation between variables and parameters observed, i.e., number of plants, number of paraste, number of Infested plants, Infested plant (%), severity index, frequency of pattern, and stem diameter (cm).

Composition and infestation of mistletoes
There There were two species and families of mistletoes found infesting trees of sengon in several cultivation patterns,i.e., S. artopurpurea (Family Loranthaceae) and V. ovalifolium (Family Santalaceae) (Figure 2).The number of S. artopurpurea is more than V. ovalifolium with parasite number of 906 individuals while V. ovalifolium was 100 individuals (Tabel 4).The domination of S.artopurpea was caused by the more population number of trees infested by S. artopurpurea during many years before (Table 4).It will accelarate distribution and aggregation of S. artopurpurea into new or old sengon trees.
There is significant positive correlation between the number of infested trees and the number of parasite (Table 5).It was also occurred between the number of infested trees and the number of mistletoe D. pentandra in Cassia fistula in Purwodadi Botanic Garden [15]and mango in Bangkalan Madura [9].High abundance of sengon has advantage to birds as mistletoes dispersers to be specific in dispersing and aggregating S. artopurpurea and V.ovalifolium in sengon trees.
The infested trees by mistletoes as sources of parasites have important role and affect significantly to mitletoes' dispersal in community.Mistletoes will not found infesting trees if there are not mistletoes as source of new parasites seedlings in communities.Solikin [9] reported that the absence of parasite S. artropurpurea in fruit plants in Bangkalan Regency East Java caused this mistletoe species not found in this region.Note : * = significant (0.01<P<0.05), ** =very significant (P<0.01),ns = non significant (P>0.05) Stem diameter and canopy size of host trees also affect on the mistletoes abundance on host species.The size of the trees had significant positive correlation to population of parasite D. pentandra in Cassia fistula in Purwodadi Botanic Garden [15].Probability of misletoes infestation increased by increasing stem size [25].Figure 3 showed that the number of parasite increased following the increasing of stem diameter with equation model y = 0.202x -1.579 with R² = 0.961.The large size of trees in tangerine citrus + vagetables + sengon pattern with diameter 35.2 cm has high potency for mistletoes' distribution and aggregation in this pattern such as showed in Table 2 that infestation of mistletoe in this pattern was the highest (8.20 individuals per plant) among the other pattern.
The birds as the mistletoes' disperser more like moving and perching on higher and larger plants so that the parasites more discovered on the top of the larger and higher trees [26].The larger and older the trees, they more attractive to frugivorous birds for perching and depositing mistletoe seeds on the branches and twigs.Figure 4 showed that the parasitic plants infesting sengon's trees decrease by decreasing of their stem diameter, and increase by increasing stem diameter.Mistletoe seedlings can remain autotrophic for several months before penetrating the tissues of the hosts so that establishing connection with the host vascular tissues is essential for their longerterm survival [27] so that diameter of branches or twigs have role in survival mistletoes life.The severity index (SI) of mistletoes in sengon cultivation pattern varied between 0.00 -15.00 (none -light) depended on the number of host,infected host, and parasite.The highest of SI was reached in tangerine + sengon pattern, i.e., 15.00.It was caused by most infected plant among the other patterns, i.e., 75 % (Table 4).It is also caused by the high number of mistletoe per plant (10.33 per plant).

Number of Mistletoe
The average of SI in cultivation patterns of sengon was categorized as low with average of SI, i.e., 5.28 and number of mistletoe i.e., 4.04 individual per cultivation patterns.It may be caused by varying harvested time (age) of trees conducted in relatively short time ( 5-7 years).These caused many mistletoes in trees as sources of new seedling parasite were removed out from the fields and trees during the trees harvesting.It contribute in decreasing number of infested trees and parasitic plants as source of parasite.Removing of the parasitic plants by pruning or stem cutting during plants cultivation affected in population of mistletoes on citruses [13] and plants collection in Purwodadi Botanic Garden [11]; [28].This low categorize of severity index indicates that control management of parasites was going well or the dispersal of the parasites is controled naturally by planting of trees in various ages and diameters.Mistletoes commonly have not infested in young and small diameters trees as showed in Figure 4.
There were other mistletoes discovered in Malang infesting trees such as M. cochinchinensis and D. pentandra [9], however these mistletoes have not been obtained infesting in sengon trees (Table 4).It indicated that sengon to be specific host for S. artopurpurea and V. ovalifolium in Malang Regency.The specificity of S. artopurpurea in particular species such as Albizia lebbekoides and A. chinensis was also reported in tree plants collection in Purwodadi Botanic Garden [28].However, mistletoes could be as host generalists or specialists, depending on several inherent and external factors, including host plant characteristics (abundance, diversity, height, age, diameter, and compatibility), season, pathogen, and dispersal patterns [29].

Cultivation patterns of sengon and trees compotition
There were sixteen patterns of sengon cultivation discovered in Malang Regency during observation (Table 6).However, this patterns are dynamics depended on several factors such as time, social, economic, biotics, and abiotics.Economical factor is the most dominant in considering to determine and decide the patterns of cultivation choosed by farmers [7].The monoculture pattern of sengon has the most number of parasite with the parasite number of 258 individuals founded in 32 plots (24.06%).It was caused by the most number of trees (597 individuals), infested trees (63 individuals), and plot (32 plots) (Table 4).Whereas, the pattern of sengon +elephant grass +cacao+clove, coffea +sengon, and sengon + papaya has no parasitic plants on sengon trees (Table 4).It may be caused by accident during the observation that no infested trees as sources of parasites which will be dispersed and distributed by birds in these patterns.
There were 26 species of tree species consisted of 25 genera and 15 families found in sengon cultivation patterns (Table 6).There were not parasitic plants infested tree plant species in the plots, except sengon (Table 6).It indicate that there was specificity of the mistletoe to infest on certain host tree species, F.moluccana.Okubamichael et al. [30] reported that high population of certain tree species accelerated the speficity of parasitic plants to certain tree species.Table 6 showed that population of F. moluccana is the most among other timber trees planted by farmers.It will attract birds as mistletoes dispersers to distribute and aggretate fruits of mistletoes from infected trees into new or old F. moluccana trees that will grow as new parasitic plants.The abundance and domination of F. moluccana is showed by its highest IVI, i.e., 238 (Table 6).There is also significant positive correlation between IVI and the number of parasitic plants in cultivations with equation model of y = 3.065x + 1. 91 and R² = 0.862 (Figure 5).

Figure 1 .
Figure 1.Map of location: A= Malang Regency East Java Indonesia; B= observation zones in Malang Regency ( )

Figure 3 .
Figure 3.The relationship between the stem diameter and the number of parasitic plants in F.Moluccana.

Figure 4 .
Figure 4.The relationship between stem diameter and infestation of parasitic plants in F. moluccana.

Figure 5 .
Figure 5. Relationship between IVI and the number of parasitic plants in F. Moluccana.4.ConclusionThere were two species of parasitic plants discovered infesting sengon (Falcataria moluccana) in sixteen cultivations patterns of sengon in Malang Regency, i.e., S. artopurpurea and V. ovalifolium.S. artopurpurea is the most dominant and specific mistletoe infested in sengon trees.Infestation and composition of mistletoes on cultivation patterns of sengon is dynamics.Monoculture pattern of sengon has the most infested and total number of trees also parasite number discovered in Malang Regency, i.e., 63. 597, and 263 individuals, respectively.The heaviest severity index of mistletoes infestation was found in tangerine citrus + sengon ,i.e.,15.

Table 1 .
The number of block and plots in cultivation patterns of sengon (F.moluccana) in Malang Regency.

Table 2 .
Score and number of parasite.

Table 3 .
Category of severity index on host plants by parasitic plants.

Table 4 .
The tree of sengon and mistletoes in various cultivation patterns of sengon in Malang Regency East Java.

Table 5 .
Correlation between several variables and parameters observed in sengon cultivation patterns in Malang Regency.

Table 6 .
Composition of tree plant species and their IVI in sengon cultivation zones in Malang Regency.