Potency of Papaya Leaf (<i>Carica papaya</i> L.) as Toxicant and Repellent against German Cockroach (<i>Blattella germanica</i> L.)

Detection of Voltage-Gated Sodium Channel (VGSC) Mutation in Deltamethrin-Resistant Blattella germanica L. from Indonesia

&lt;b&gt;Background and Objective:&lt;/b&gt; German cockroach (&lt;i&gt;Blattella germanica&lt;/i&gt; L.) is one of the most common residential pests in Indonesia. Controlling the population face obstacles due to insecticide resistance, especially to deltamethrin. This research investigated the resistance status and the possibility of a Voltage-Gated Sodium Channel (VGSC) knockdown resistance mutation (L1014F) in two field strains of German cockroaches collected from two cities in Indonesia (Bukittinggi, named RMKN-BKT and Bandung, named KRSA-BDG) with VCRU-WHO as the standard strain. &lt;b&gt;Materials and Methods:&lt;/b&gt; This study started with a bioassay test to determine the lethal dose of 50% (LD&lt;sub&gt;50&lt;/sub&gt;) for each strain and followed by a molecular test for mutation detection. &lt;b&gt;Results:&lt;/b&gt; The results showed that the RMKN-BKT and KRSA-BDG strains were highly resistant to deltamethrin with RR50 values of 80,090 times and 73,272 times, respectively. Only the RMKN-BKT strain was shown to carry L1014F kdr mutation which lead to an amino acid replacement from leucine (TTG) to phenylalanine (TTC). Two silent mutations were also found in both field strains at codons 983 (TGC/cysteine→TGT/cysteine) and 984 (GGG/ glycine→GGA/glycine) which were suggested as polymorphism phenomena. The absence of the L1014F mutation in the Bandung strain does not exclude the possibility of the presence of the VGSC mutation at other points. &lt;b&gt;Conclusion:&lt;/b&gt; It requires subsequent investigation in mutation detection at other points and the possible presence of other resistance mechanisms to get a precise solution in the population control. Bioinsecticides may stand as a breakthrough so that the strategy will no longer focus on insecticides.

Efficacy of Noni (Morinda citrifolia L.) Ethanolic Leaf Extract Against German Cockroach (Blattella germanica L.)

&lt;b&gt;Background and Objective:&lt;/b&gt; The ethanol extract of noni leaves (&lt;i&gt;Morinda citrifolia&lt;/i&gt; L.) can be used as insecticides to control populations of German cockroaches that have been resistant to synthetic insecticides. This study aimed to determine the potency of the ethanol extract of noni leaves to kill and repel German cockroaches and affect the amount of food consumed. &lt;b&gt;Materials and Methods:&lt;/b&gt; The methods used in this study were the contact toxicity test, the repellency test and the food consumption test. The noni leaves extract and German cockroach populations were provided in the laboratory. &lt;b&gt;Results:&lt;/b&gt; The noni leaves extract concentration of 20% (residue of 3.14 mg cm&lt;sup&gt;2&lt;/sup&gt; &lt;sup&gt;1&lt;/sup&gt;) was very effective in killing the standard population and effective in killing the field population of German cockroaches. The sub-lethal concentration noni leaves extract of 0.36% (residue 0.056 mg cm&lt;sup&gt;2&lt;/sup&gt; &lt;sup&gt;1&lt;/sup&gt;) and 1.08% (residue 0.169 mg cm&lt;sup&gt;2&lt;/sup&gt; &lt;sup&gt;1&lt;/sup&gt;) was very high grade as repellent of German cockroaches. The sub-lethal concentration of noni leaves extract did not inhibit the amount of food consumption in German cockroach populations. &lt;b&gt;Conclusion:&lt;/b&gt; Leaves of noni plants can be used as bioinsecticides to control German cockroach populations that have been resistant to commercial insecticides.