Uncle Guo put forward a test, and it was a test for Yu Fan and Guo Na, and he didn't know what medicine was sold in the gourd.

Guo Na said to Uncle Guo coquettishly: "Dad, don't be embarrassed by your eldest brother, what are you doing." ”

Uncle Guo waved his hand and said to Guo Na: "It's not that I deliberately make things difficult for you, it's that we've really encountered tricky things recently, and I wanted to ask you about this when you came back to help. ”

Yu Fan smiled and said, "Uncle, it's okay to say it, let's see if we can help." ”

Uncle Guo: "Hey, it's actually not a big deal, it's our pet shop, there have been cockroaches recently, we didn't care about it at first, and now it's out of control." ”

Guo Na asked strangely: "What are cockroaches afraid of, spray them with insecticides, won't it be over?" ”

Uncle Guo shook his head helplessly: "Yes, we used insecticide to spray at the beginning, and it really worked, as soon as we sprayed the cockroaches, they turned over, we went up and trampled them to death, and then disposed of them, and the cockroaches did disappear for a while, but they came out again in a few days, and there were more." Not only more, but they also ran to the dashboard of the rice cooker, the water dispenser, and disgusted us. ”

Guo Na was puzzled: "Then continue to spray with pesticides." ”

Uncle Guo sighed: "Here's the problem, this time we sprayed with pesticides, and they seemed to be immune, and there was no reaction at all." ”

Guo Na then asked, "Then increase the dose?" ”

Uncle Guo: "We also tried to increase the dose, but it didn't work." And we have so many dogs in our store, we are worried that the dogs will be poisoned if they are sprayed with too much insecticide. Don't dare to take any more drastic drugs. ”

Guo Na held his chin: "Well, this is indeed a bit tricky." Guo Na looked up at Yu Fan, who was also thinking, and asked, "Brother Yu, do you have any good ideas?" ”

Yu Fan pondered for a few seconds, pursed his lips, and said: "The characteristics of cockroaches in the north and those in the south are actually very different, and there are some differences in dealing with them. The Southern Cockroach is the size of a lighter. The northern cockroach is only the size of a peanut. The species of the southern cockroach belongs to the American cockroach and has butterfly-shaped brown markings in the middle of the dorsal plate of the prothorax. The northern cockroach belongs to the German cockroach and has two parallel black-brown longitudinal lines on the dorsal plate of the prothorax. ”

Guo Na added: "Yes, I remember the first time I saw the southern cockroach, it scared me. ”

Yu Fan continued: "When dealing with cockroaches in the north, you must pay attention to the fact that you must not crush the cockroaches, after the cockroach is trampled, its eggs will burst and scatter, you can imagine that it is a hornet's nest, so that it will not be long before the baby cockroaches hatch out and will be everywhere." The right thing to do is to dismember the corpse of the cockroach and flush it down the drain. So the cockroaches broke out after a few days of rest, but they were actually the seeds you put in. ”

Yu Fan paused and continued: "The growth process of cockroaches is: eggs→ larvae → adults, and they can lay 4-17 egg clips in their lifetime, and each egg clip has 20-50 eggs. There is an unwritten saying that when you see a cockroach, there are already 40 cockroaches around. What's even more terrifying is that cockroaches, a species with strong vitality and adaptability, are highly resistant, and if your insecticide can't kill them all at once, they will develop antibodies to the drug, and spraying them will no longer work. ”

Guo Na summed it up: "So the group of 'Xiaoqiang' we are facing now is actually an evolved super cockroach? ”

Yu Fan: "I'm afraid so. ”

Uncle Guo asked anxiously, "Then what should I do?" Is there no way around it? ”

Guo Na: "I remember that there seems to be a cockroach bait glue sold on the Internet, which can get rid of cockroaches, do you want to try it?" ”

Yu Fan thought for a while: "Well, this should be fine, but the toxicity may be a little strong, if it is eaten by a dog, it will definitely be poisoned." ”

Uncle Guo: "What then?" ”

Everyone was at a loss. At this time, Guo Na's mother, Aunt Cao, came back.

Uncle Guo immediately introduced Yu Fan to Guo Na's mother, and this Aunt Cao also praised Fan.

Without waiting for any greetings, Yu Fan suddenly saw a bag of white sugar in the vegetable basket that Aunt Cao brought back.

Yu Fan asked, "Auntie, did you buy candy?" ”

Aunt Cao didn't know why Yu Fan asked this, but she still replied: "That's right, Lao Guo said that he was going to make dumplings for his daughter tonight, so I bought some white sugar to use when I was going to make a dipping dish." ”

Yu Fan suddenly clapped his hands and shouted: "There is!" ”

Yu Fan said: "Guo Na, please help me get some laundry detergent, Auntie, please give me some sugar, I want to configure a cockroach remover!" ”

Guo Na brought laundry detergent, Yu Fan mixed the laundry detergent and sugar together, and then put the mixture on a piece of white paper and put it on the countertop of the bathroom.

Uncle Guo was puzzled: "Can this thing kill cockroaches?" Aren't all pesticides useless? ”

Yu Fan smiled and explained: "The body surface of insects uses wax shells to moisturize. Cockroaches are no exception, and almost all laundry detergents add sodium tetraborate (borax) as a modifier. Borax destroys the wax shells of insects, causing them to become dehydrated. Cockroaches also have the same feeding habits, and the cockroaches killed by boron will be eaten by their peers, causing boron to gradually enter the entire cockroach community system. If the boron level is too high, the cockroach egg sheath will also dry and inactivate, eventually leading to the extinction of the community. ”

Guo Na also understood at once: "So that's the case, the insecticide is not good, then we will use boron as a carrier, let it enter the cockroach population, let the cockroaches lure the wolf into the house, and then kill each other." ”

Yu Fan continued: "This method is relatively low toxicity and more practical. Insecticides on the Internet often only consider the effect, and the toxicity is very high, and with the continuous enhancement of cockroach resistance, the toxicity of insecticides is also getting higher and higher, which creates a safety hazard. With our homemade, it is relatively safe, after all, there are so many cats and dogs in pet stores, and poisoning is a big trouble. ”

Aunt Cao patted Yu Fan on the shoulder and said approvingly: "Young man, yes, very smart, you are Guo Na's master, teach my daughter more in the future." ”

Aunt Cao turned her face to Guo Na again and said, "Look at you, you are about the same age as you, but people are better than you in terms of professional knowledge and life, you have to learn more." ”

Guo Na stuck out his tongue and made a very innocent look.

Yu Fan thanked his aunt for her praise again and again, although Guo Na's parents were not highly educated, they were still very sensible.

While chatting, Guo Na and Yu Fan's mobile phones suddenly rang, and they took out their mobile phones at the same time.

It was Chen Zhenyang's message, which read: "Chen Tizhou's case has made progress again, and Officer Ziyan from Jinbu Town has provided us with a new clue." On Monday, let's go! ”

It seems that there are busy again.