TY - JOUR AU - Richard Gorham, J. PY - 1962/07/01 Y2 - 2024/03/29 TI - Insecticide Resistance-Susceptibility Tests with German Cockroaches (Blattella germanica Linnaeus) in Puerto Rico JF - The Journal of Agriculture of the University of Puerto Rico JA - JAUPR VL - 46 IS - 3 SE - Articles DO - 10.46429/jaupr.v46i3.12338 UR - https://revistas.upr.edu/index.php/jaupr/article/view/12338 SP - 219-225 AB - Adult males and females of a strain of <em>Blattella germanica</em> cultured from collections made in the School of Medicine, San Juan, P.R., were tested for insecticide resistance-susceptibility. According to the LT50 test these cockroaches demonstrated resistance to chlordane (â™, and ♀ LT50 &gt; 72), lindane (â™, LT50 = 7); ♀, 6), and dieldrin (â™, and ♀ LT50 &gt; 72), but were susceptible to malathion (â™, LT50 = 1.75; ♀, 1.25). Lethal concentrations at the 50- and 90-percent levels, estimated on the basis of combined counts of "dead" and "moribund" insects, indicated that the cockroaches are susceptible to the following insecticides, listed in decreasing order of effectiveness: Bayer 29493 (â™, LC50 = 0.007; ♀, 0.012; â™, LC90 = 0.016; ♀, 0.024), diazinon (â™, LC50 = 0.02; ♀, 0.01; â™, LC90 = 0.05; ♀, 0.02), synergized malathion (â™, LC50 = 0.07; ♀, 0.1; â™, LC90 = 0.12; ♀, 0.15), and malathion (â™, LC50 = 0.13; ♀, 0.08; â™, LC90 = 0.35; ♀, 0.2). ER -