ɛkspˈiəɹɪənst ɡˈɑːɹdənɚz wˈɑːtʃ ðə stˈɛmz fɔːɹ sˈaɪnz ʌv fɹˈæs pɹətɹˈuːdɪŋ fɹʌm smˈɔːl hˈoʊlz, wˌɪtʃ ɪz ɐn ˈɪndᵻkˌeɪɾɚɹ ʌvðə pɹˈɛzəns ʌvðə lˈɑːɹvə ɪnsˈaɪd.
Experienced gardeners watch the stems for signs of frass protruding from small holes, which is an indicator of the presence of the larva inside.