Comprehensive Investigation of Die-Back Disease Caused by Fusarium in Durian.

Durian (Durio zibethinus L.) is an economically important crop in the southern and eastern parts of Thailand. The occurrence of die-back disease caused by plant pathogenic fungi poses a serious threat to the quality and quantity of durian products. However, the identification of causal agents has been a subject of mixed information and uncertainty. In this research, we conducted a comprehensive investigation of die-back disease in nine durian plantations located in Thailand. By analyzing a total of 86 Fusarium isolates obtained from infected tissues, we aimed to provide clarity and a better understanding of the fungal pathogens responsible for this economically significant disease. Through a combination of colony characteristics, microscopic morphology, and a multilocus sequence analysis (MLSA) of the internal transcribed spacer (ITS) region, translation elongation factor 1-α (TEF1-α) gene, and RNA polymerase II gene (RPB2) sequences, we were able to identify and categorize the isolates into three distinct groups, namely, Fusarium incarnatum, F. solani, and F. mangiferae. Koch's postulates demonstrated that only F. incarnatum and F. solani were capable of causing die-back symptoms. This research represents the first report of F. incarnatum as a causal agent of die-back disease in durian in Thailand. Additionally, this study uncovers the association of ambrosia beetles and F. solani, highlighting the potential involvement of E. similia in facilitating the spread of die-back disease caused by Fusarium in durian.

Geometric Morphometric Analysis and Molecular Identification of Coconut Mite, Aceria guerreronis Keifer (Acari: Eriophyidae) Collected from Thailand.

One of the most impactful pests in several coconut production regions across the world is the coconut mite, Aceria guerreronis Keifer. Scholars can obtain some necessary biogeographic information about coconut mites from studies that explore the geographic patterns of morphological variations and molecular properties among coconut mite populations from various locales. To investigate the geographical origin, ancestral host associations, and colonization history of the mite in Thailand, we obtained DNA sequence data from two mitochondrial (16s and COI) and one nuclear region (ITS) from coconut mite samples originating from 25 populations; additionally, we analyzed the morphological variations in the prodorsal shield and the coxigenital and ventral regions of the mite idiosoma. From the results of experiments using both identification methods, we identified the mite as the coconut mite, A. guerreronis (Acari: Eriophyidae). According to the phylogenetic analysis results of the 25 mite samples, we classified the mites as being closely related to mites found by the authors of a previous report in India. We are the first to report the results of a geometric morphometric analysis and molecular identification of A. guerreronis in Thailand, and our findings support the idea that the mites' origin and invasion history are not well documented, which makes it difficult to apply quarantine procedures and search for biological pest control agents.

Mechanisms of Trichomes and Terpene Compounds in Indigenous and Commercial Thai Rice Varieties against Brown Planthopper.

Plant trichomes generally act as a physical defense against herbivore attacks and are present in a variety of plants, including rice plants. This research examined the physical and chemical defenses of rice plants against the brown planthopper (BPH), Nilaparvata lugens (Stål) (Hemiptera: Delphacidae). A total of 10 rice varieties were used in this study. An electron microscope was used to observe trichomes. Constitutive and induced volatile compound profiles were assessed using GC-MS analyses. The preference of BPH for volatiles from the 10 rice plants was tested using a two-choice arena olfactometer system. The density of prickle trichomes had a negative relationship with the BPH injury level. Without BPH infestation, the volatile of the most resistant rice variety (Rathu Heenati (RH)) was preferred by BPH than those of the other varieties, with the exception of Gled Plah Chawn. However, the relative BPH preference for volatiles from the RH variety decreased during BPH infestation. When rice plants were infested by BPH, the numbers of VOCs and these quantities decreased. In the RH variety, the emission of essentities found without BPH infestation ceased during infestation by BPH. During the BPH infestation, rice plants started to emit new VOCs that were not detected before the BPH infestation started. In conclusion, we discovered that rice plants defended against BPH by changing VOC components during BPH infestation and ß-Sesquiphellandrene was likely the most effective component.

Morphological and Molecular Identification of Plant Pathogenic Fungi Associated with Dirty Panicle Disease in Coconuts (Cocos nucifera) in Thailand.

Dirty panicle disease in coconuts (Cocos nucifera) was first observed in the KU-BEDO Coconut BioBank, Nakhon Pathom province, Thailand. The occurrence of the disease covers more than 30% of the total coconut plantation area. The symptoms include small brown to dark brown spots and discoloration of male flowers. Herein, three fungal strains were isolated from infected samples. Based on the morphological characteristics the fungal isolates, they were classified into two genera, namely, Alternaria (Al01) and Fusarium (FUO01 and FUP01). DNA sequences of internal transcribed spacer (ITS), glyceraldehyde 3-phosphate dehydrogenase (GAPDH), translation elongation factor 1-α (tef1-α), and RNA polymerase II second largest subunit (rpb2) revealed Al01 as Alternaria burnsii, whereas DNA sequences of ITS, rpb2, and tef1-α identified FUO01 and FUP01 as Fusarium clavum and F. tricinctum, respectively. A pathogenicity test by the agar plug method demonstrated that these pathogens cause dirty panicle disease similar to that observed in natural infections. To the best of our knowledge, this is the first report on the novel dirty panicle disease in coconuts in Thailand or elsewhere, demonstrating that it is associated with the plant pathogenic fungi A. burnsii, F. clavum, and F. tricinctum.

A new species and a new synonym in the scarab genus Parastasia Westwood, 1841 (Coleoptera: Scarabaeidae: Rutelinae), with a key to species from Thailand.

Ten species of the genus Parastasia Westwood, 1841 including a new species and a new record are recorded from Thailand. We here describe Parastasia spinosa Hongsuwong, Sanguansub & Jaitrong, new species from eastern Thailand based on a male specimen. Parastasia bimaculata (Guérin-Méneville, 1843) is recorded for the first time in Thailand. We confirm that Parastasia bigibbosa Nonfried, 1891 occurs in the country. Parastasia andamanae (Ghai, Chandra & Ramamurthy, 1988) is synonymized with P. bigibbosa. A key to the Thai Parastasia species is provided.

Revision of the genus Xylodrypta Lesne 1901 (Coleoptera: Bostrichidae: Bostrichinae: Xyloperthini) with a new species and a key to species.

We revise the monospecific bostrichid genus Xylodrypta Lesne 1901, and describe a new species, X. lanna Liu Beaver from Thailand and Laos. A key is given to distinguish the two species of Xylodrypta.

Parasitism of Soldiers of the Termite, Macrotermes gilvus (Hagen), by the Scuttle Fly, Megaselia scalaris (Loew) (Diptera: Phoridae).

Termites of the genus Macrotermes (Termitidae: Macrotermitinae) are serious agricultural and structural pests, which also play vital roles in ecosystem functioning, and are crucial for the maintenance of tropical biodiversity. They are widely distributed, mainly in Southeast Asian countries; however, the parasitism of termites has been little researched. This research was conducted to identify and study the ecology of the parasitoids of termites at Kasetsart University, Kamphaeng Saen Campus, Nakhon Pathom, Thailand. Macrotermes gilvus (Hagen) soldier termites were collected from 25 mounds. In four of the 25 mounds, scuttle fly larvae were found inside the bodies of the soldier termites, and adult flies were found in all of the mounds. Some of the larvae successfully developed to pupae under laboratory conditions. The percentages of parasitized major soldier termites collected from the four mounds were 43.79%, 47.43%, 0.86%, and 3.49%, respectively, and the percentages of parasitized minor soldier termites were 0.64%, 0.00%, 0.21%, and 0.00%, respectively. Larvae, pupae, and adult flies were identified using both morphological and molecular identifications. Molecular identification used the partial nucleotide sequences of the mitochondrial cytochrome c oxidase I (COI) gene. The results of both identification methods identified the parasitic Diptera as the scuttle fly, Megaselia scalaris (Loew) (Diptera: Phoridae). The phylogenetic analysis of the 23 scuttle fly samples (11 larvae, 7 pupae, and 5 adults) classified them into two clades: (1) Those closely related to a previous report in India; (2) those related to M. scalaris found in Asia and Africa. This is the first discovery of M. scalaris in M. gilvus. Further investgation into termite parasitism by M. scalaris and its possible use in the biological control of termites is needed.

A review of the genus Dryocoetiops Schedl, with new species, new synonymy and a key to species (Coleoptera: Curculionidae: Scolytinae).

Eighteen species currently placed in the genus Dryocoetiops Schedl, 1957, are reviewed. Two new species are described: Dryocoetiops pasohensis Beaver, Smith and Sanguansub, D. salebrosus Beaver, Smith and Sanguansub. The following new synonymy is proposed: Dryocoetiops apatoides (Eichhoff, 1875) (= Taphrorychus striatus Nobuchi, 1966, syn. n.); Dryocoetiops moestus (Blandford, 1894) (= Dryocoetes australis Schedl, 1942, syn. n., Dryocoetes coffeae Eggers, 1923, syn. n., = Dryocoetes dinoderoides Blandford, 1894, syn. n., = Dryocoetes eugeniae Schedl, 1942, syn. n., = Dryocoetes hirsutus Schedl, 1939, syn. n., = Dryocoetes javanus Eggers, 1936, syn. n., = Dryocoetes malaccensis Schedl, 1942, syn. n., = Pseudopoecilips taradakensis Murayama, 1957, syn. n., = Dryocoetes tonkinensis Schedl, 1942, syn. n.); Dryocoetiops semigranulatus (Eggers, 1936) (= Dryocoetes kepongi Schedl, 1953, syn. n.). The following new combinations are proposed: Coccotrypes flavicornis (Blandford, 1895) comb. n.; Procryphalus petioli (Beaver, 1990) comb. n., both from Dryocoetiops. A key is provided to the females of ten species remaining in Dryocoetiops; males remain unknown in the genus. The taxonomy, distribution and biology of the species are briefly reviewed, and some new distributional records included.

A new species of Lobesia Guenée, 1845 from Thailand (Lepidoptera: Tortricidae: Oletheutinae).

Lobesia bisacca Charoensub and Pinkaew, n.sp., is described from Thailand. Specimens were collected in light traps in Trat Province, eastern Thailand and were deposited in the Kasetsart Kamphaengsaen Insect Collection. The new species can be distinguished from all other congeners by the unusual, long, protruding process from the base of the sacculus in the male genitalia. Illustrations of the adult, male genitalia, and male secondary characters are provided.

An annotated checklist of Platypodinae and Scolytinae (Coleoptera: Curculionidae) from Iran.

We provide an annotated checklist of species of bark and ambrosia beetles (Curculionidae: Platypodinae and Scolytinae) recorded from Iran, with information on distribution, host trees, biology and taxonomy. Two species of Platypodinae and 79 species of Scolytinae are recorded. Hypothenemus crudiae (Panzer, 1791), Scolytus koenigi Schevyrew, 1890 and Xyleborus monographus Fabricius, 1792 are recorded for the first time from Iran. Previous records of three further species are considered dubious and require confirmation.

A review of the genus Carchesiopygus Schedl (Coleoptera: Curculionidae: Platypodinae), with keys to species.

The ten species included by Schedl (1972) in the Oriental platypodine genus Carchesiopygus Schedl are reviewed. The genus is rediagnosed and restricted to the following species: Carchesiopygus wollastoni (Chapuis) (type species), C. alternantes Schedl, C. assamensis (Beeson), C. impariporus (Beeson), C. multidentatus (Strohmeyer) and C. oculatus (Beeson), and distinguished from Crossotarsus Chapuis and related genera. The following species are transferred to Platypus Herbst: Carchesiopygus dentipennis Schedl, Carchesiopygus lobacanthus Schedl, Crossotarsus acanthurus Beeson, Crossotarsus psilacanthurus Beeson. Keys are provided to males and females of Carchesiopygus. The taxonomy, distribution and biology of the species are briefly reviewed, and some new records included.

Comparison of Sapwood Discoloration in Fagaceae Trees After Inoculation with Isolates of Raffaelea quercivora, Cause of Mass Mortality of Japanese Oak Trees.

The mass mortality of oak trees has been prevalent in Japan since the late 1980s. The fungus Raffaelea quercivora is transmitted by an ambrosia beetle, Platypus quercivorus, which causes mortality. The beetle is able to bore galleries into the sapwood of most Fagaceae trees in Japan; however, the level of mortality caused by R. quercivora and P. quercivorus differs greatly among tree species. Previous studies by our research group have demonstrated that the virulence of R. quercivora differs among isolates when inoculated into Quercus serrata logs. However, interactions between the virulence of R. quercivora isolates and the susceptibility of other fagaceous species have yet to be elucidated. In this study, we inoculated the fresh logs of 11 fagaceous species with isolates of low and high virulence, and measured the tangential widths of discolored sapwoods 3 weeks after inoculation. Although the discoloration widths of Q. crispula sapwood were similar among all isolates, those of Q. serrata and Q. acutissima tended to increase with the more virulent isolates. Sapwood discoloration in Q. glauca, Q. acuta, Q. salicina, Lethocarpus edulis, and Castanopsis sieboldii was greatly increased by highly virulent isolates. Discoloration in Fagus japonica was not influenced by any of the isolates. The logs of Q. crispula and Q. serrata but not Q. glauca were significantly more discolored by a low-virulence isolate compared with standing trees. The various virulent isolates induced unique sapwood discoloration characteristics in each species, which may explain species-specific differences in mortality rates.